A DFT rationalization of the room temperature photoluminescence of Li 2 TiSiO 5

Size: px
Start display at page:

Download "A DFT rationalization of the room temperature photoluminescence of Li 2 TiSiO 5"

Transcription

1 Chemical Physics Letters 398 (2004) A DFT rationalization of the room temperature photoluminescence of Li 2 TiSiO 5 E. Orhan a,b, *, V.C. Albarici b, M.T. Escote b, M.A.C. Machado c, P.S. Pizani c, E.R. Leite b, J.R. Sambrano d, J.A. Varela a, E. Longo b a Instituto de Química, Universidade Estadual Paulista, Araraquara, SP, Brazil b Departamento de Química, Universidade Federal de São Carlos, Via Washington Luiz, Km. 235, Caixa Postal 676, São Carlos, SP, Brazil c Departamento de Física, Universidade Federal de São Carlos, P.O. Box 676, São Carlos, SP, Brazil d Laboratório de Simulação Molecular, DM, Universidade Estadual Paulista, P.O. Box 473, Bauru, SP, Brazil Received 31 July 2004; in final form 16 September 2004 Available online 7 October 2004 Abstract Li 2 TiSiO 5 powders were synthesized by the polymeric precursor method. The calcination temperatures were progressively increased until the complete crystallization of the phase occurring at 870 C. For the first time, a strong photoluminescence was measured at room temperature with a 488 nm excitation wavelength for the non-crystalline samples. This photoluminescence in disordered phases has been interpreted by means of high-level quantum mechanical calculations based on density functional theory. Two periodic models have been used to represent the crystalline and disordered powders. They allowed to calculate electronic properties consistent with experimental data and to explain the relations between photoluminescence and structural disorder. Ó 2004 Elsevier B.V. All rights reserved. 1. Introduction In the last years, the interest in development of new photoluminescent (PL) materials with several potential applications has rapidly grown. Our group has reported that the PL phenomena are related to the structural disorder [1 3]. In particular, Leite and co-workers [2,4,5] have found an intense visible photoluminescence at room temperature in amorphous ATiO 3 compounds prepared by sol gel method. It has been shown by XANES [6,7] studies that the peculiarity of those compounds is the coexistence of two types of Ti coordination, fivefold and sixfold. The higher the heat treatment temperature, the rarer the pentacoordination. Bouma and Blasse [8] presented the dependence of luminescence of A 2 TiOBO 4 (A = Li, Na; B = Si, Ge) * Corresponding author. address: (E. Orhan). titanates on their crystal structure. These authors have reported that titanates where exist TiO 6 clusters containing a short Ti O bond, show efficient PL at room temperature if these octahedra are isolated from each other, and ascribed this effect to a broadening of energy bands. In particular, the compounds with A = Li (Li 2 Ti- BO 5 ) are strongly luminescent when excited by a 250 nm wavelength. In this Letter, we present outstanding measurements of a broad PL band at room temperature as a function of heat treatment of tetragonal lithium-titanosilicate, Li 2 TiSiO 5 [9] and ab initio periodic quantum-mechanical calculations based on density functional theory (DFT) to investigate the origin of this PL in function of structural parameters and electronic properties. Li 2 TiSiO 5 has never been the object of a theoretical investigation up to now, but we insist in the necessity of confronting it with experimental results for achieving a far more complete investigation. The aim of our syn /$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi: /j.cplett

2 E. Orhan et al. / Chemical Physics Letters 398 (2004) ergetic strategy between experimental results and electronic structure is not to explain how PL occurs, as many valid hypothesis already exist [10,11], but to explain why it occurs at room temperature of PL in the non-crystalline powders. 2. Experimental procedure The soft chemical processing used to synthesize the Li 2 TiSiO 5 powders, polymeric precursor method [12,13], is based on the formation of soluble coordination compounds followed by a polymerization. Titanium isopropoxide, tetraethylortosilicate (TEOS) and lithium nitrate were dissolved in an alcoholic solution of citric acid (CA). After homogenization of the metallic precursors, ethylene glycol (EG) was added to promote the polymerization by polyesterification reaction between heterometallic CA complex and EG. The CA/ EG ratio was fixed at 60/40 (mass ratio) and the molar ratio between the lithium, titanium and silicon cations was 2:1:1. After polymerization at 90 C/1 h, the formed polymeric precursor was calcinated at 350 C/1 h to promote pre-pyrolysis. The heat treatment was carried out at 500, 600 and 700 C for 4 h, and at 870 C for 24 h at a heating rate of 5 C/min. The powders obtained were structurally characterized by X-ray powder diffraction (XRD) (Cu Ka radiation). The diffraction patterns were performed on a Rigaku D/Max-2400 diffractometer using the Cu Ka radiation. Typical 2h angular scans ranging from 20 to 60 in steps varying of 0.02 were used. The room temperature PL spectra of Li 2 TiSiO 5 powders were taken with a U1000 Jobin Yvon double monochromator coupled to a cooled GaAs photomultiplier and a conventional photon counting system. The exciting wavelength of an argon ion laser was used, with the laserõs maximum output power kept at 20 MW. A cylindrical lens was used to prevent the sample from overheating. The slit width used was 100 lm. 3. Computational method and models Periodic ab initio quantum-mechanical calculations performed with the B3LYP hybrid functional [14,15] have been carried out by means of the CRYSTAL98 computer code [16]. This functional has already been successfully employed in studies on the electronic and structural properties of the bulk and surfaces of TiO 2 [17], PbTiO 3 [18] and Ba 0.5 Sr 0.5 TiO 3 [19] systems. The standard 6-31G* basis set was selected for oxygen atom. For the Ti, Li and Si atoms we selected, respectively, d4-1G*, 6-1G*, 8-41G* [20]. The k-points sampling was chosen to be 40 points within the irreducible part of the Brillouin zone. The crystal structure is composed by TiSiO 5 layers bound by Li ions planes. In the layers, there are SiO 4 tetrahedra connecting TiO 5 square pyramids. However, it is also possible to consider the titanate group as distorted octahedra in which the apical bonds are alternatively short and long (cf. Fig. 1). The ground-state equilibrium geometry was obtained by minimizing the total energy per unit cell with respect to the lattice parameters and atomic positions. From this optimized structure, we have built two periodic models to represent the crystalline and disordered phases of Li 2 TiSiO 5. The first one, which will be designated as 5c, is simply the unit cell using the optimized parameters. All titanium atoms are fivefold-coordinated and the bonds between titanium and the apical oxygen, Ti O2, are alternatively 1.70 Å (O2 inside the unit cell) and 2.70 Å (O2 out of the unit cell). For the second model, 6c, the apical oxygen, O2, has been dislocated by 0.5 Å in the z direction, turning the Ti O2 bonds regular, 2.20 Å (see bottom of Fig. 1). Therefore, the titanium atom of 6c model is sixfold-coordinated. It has to be underlined here that the 6c model does not exactly represent the phases before crystallization, as they do not have a long-range organization, but is disordered as compared to the crystalline model. 4. Results and discussion Fig. 2 shows the X-ray diffraction patterns of three Li 2 TiSiO 5 powders heat treated at 500 and 600 C for 4 h and at 870 C for 24 h. The patterns obtained for the samples annealed at temperatures below 600 C revealed the possible presence of the Li 2 TiO 3 phase. However, due to the rather broad and low intense Bragg reflections, it is possible to have small amounts of other Li Ti O phases, as for example LiTi 2 O 4. In addition, the very noisy background attests for the presence of a disordered phase, an inorganic precursor which crystallization has not yet occurred. The beginning of the crystallization of the Li 2 TiSiO 5 phase occurs at temperatures close to 800 C, and it is very well crystallized after being heat treated at 870 C for 24 h. It has to be underlined that the powder melts at 900 C, and thus that 870 C is the highest temperature that has been reached without achieving the melting point. However the presence of a small amount of TiO 2 (rutile) was remarked and quantified by Rietveld refinement as being 5% [21]. The additional phases in the disordered powders as in the crystalline ones were checked to have no influence on the PL properties by individual measurements. Fig. 3 shows the PL spectra of three Li 2 TiSiO 5 powders annealed at 500 and 600 C for 4 h and at 870 C for 24 h. The highest PL intensity is observed for the 500 C annealed powder. This large band spectrum can be deconvoluted into two Gaussian-type functions,

3 332 E. Orhan et al. / Chemical Physics Letters 398 (2004) Fig. 1. Representation of two Li 2 TiSiO 5 unit cells (space group P 4/nmm ). At bottom the Ti coordinations in 5c and 6c periodic models are represented left and right, respectively. The vertical arrows illustrate the displacement of O2. Fig. 2. X-ray diffraction patterns of Li 2 TiSiO 5 powders heat treated at: (a) 500 C, (b) 600 C for 4 h and at (c) 870 C for 24 h. Fig. 3. Photoluminescence spectra excited by the 488 nm line of an argon ion laser of three Li 2 TiSiO 5 powders annealed at: (a) 500 C, (b) 600 C, for 4 h and at (c) 870 C for 24 h. Curves (1) and (2) are the plots of the deconvolution of the spectrum (a) in two Gaussian-type functions.

4 E. Orhan et al. / Chemical Physics Letters 398 (2004) one peaking at 2.08 ev (orange-red band) and the other one at 2.28 ev (green band). The powder heat treated at 600 C also exhibits a strong PL signal, however, it is shifted towards higher energies as compared to the 500 C spectrum. The green component of the 600 C spectrum is much bigger than its orange-red component, which almost vanished with the partial structural organization. This is in accordance with our previous investigations on titanates where the higher the heat-treatment temperature, the rarer the pentacoordination of titanium and the weaker the PL emission. Following the example of Macke [22], it is possible to relate the green and orange-red components of the PL bands to one particular type of titanium coordination existing in the structure, as observed by Ponader et al. [23] that detected the presence of hexa and pentacoordinated titaniums in titanosilicate glasses. The orange-red component must somehow be linked to the pentacoordinated titanium and the green component to the hexacoordinated titanium. The crystalline, fully ordered phase (870 C) does not present any PL at all when excited with the 488 nm line of the argon ion laser, only the Raman signal is visible. However, Bouma and Blasse [8] already noticed that Li 2 TiSiO 5 in its crystalline form do present PL at room temperature when excited by a shorter wavelength line (250 nm). They related this PL to the existence of isolated TiO 5 square pyramid in the structure. In order to rationalize the links between PL and structural disorder, we performed a detailed theoretical study of the electronic structure in two models, a crystalline and a disordered one. Fig. 4 represents the band structure of 5c (a) and 6c (b) models. For the 5c model, the top of the valence band (VB), coincident with the Fermi Energy (E F )is located at C point. The minimal indirect gap between C and M is 5.47 ev. The minimal direct gap at C is 5.73 ev. The top of the VB for the 6c model is at R point and bottom of conduction band (CB) is located at M, as in the 5c model. The indirect minimal gap between R and M is 3.65 ev while the minimal direct gap at C is 4.11 ev. The calculated band gap energies cannot be compared with the experimental ones as the results have been turned untrustable by the presence of the additional phases. The fact that the band gap energy decreases from the ordered to disordered models shows that it is directly linked to the degree of structural arrangement, in accordance with the energy levels linked to structural defects described by Montoncello et al. [24]. The atom-projected and total DOS of the 5c (a) and 6c (b) models are depicted in Fig. 5. In the 5c model, the VB consists mainly of 2p orbitals of O atoms, with a higher contribution of O1 atom in the upper part. In the 6c model, although the valence band is also made of the 2p orbitals of O atoms, the upper part presents a strong O2 character, the oxygen atom that was moved away from the titanium. The CB is clearly preponderantly made of the Ti (3d) states in both cases, with a weak Si contribution. In 5c model, the Ti O2 bond is shorter (and thus tighter) than the Ti O1 bonds (1.70 and 1.97 Å, respectively), this is why the upper part of VB is made of 2p O1 states: the Ti O2 interaction leads to greater splitting of the crystal orbitals. In the case of 6c model, this is the Ti O1 bond that is shorter and thus 2p O2 states fill the upper VB. We have calculated the Mulliken charge distributions of SiO 4, TiO 5 and TiO 6 clusters. In the 5c model, SiO 4 has a formal charge of 0.38 and TiO 5 of 1.47 jej. In the 6c, the charges are 0.36 and 1.49 jej for SiO 4 and TiO 6, respectively. The individual atomic charges only suffer weak variations with the structural deformation. The hypothesis we emitted throughout our studies of the origin of PL in disordered titanates [19] is that to exhibit room temperature PL, a system must fulfill two conditions: (i) to possess at least two types of differently charged clusters creating a polarization of the structure Fig. 4. Band structure for the 5c (a) and 6c (b) periodic models.

5 334 E. Orhan et al. / Chemical Physics Letters 398 (2004) Fig. 5. Total and projected DOS for the 5c (a) and 6c (b) periodic models. and (ii) to present some localized levels inside its band gap, levels that are mostly resulting of some structural disorder. The junction of those two conditions allows an easy trapping of electrons and holes during excitations and thus favors the radiative decay causing PL emission. In disordered Li 2 TiSiO 5, the two conditions are encountered and this is why the non-crystalline powders present a strong PL. In the crystalline powder, no PL emission is observed with our 488 nm excitation wavelength because it corresponds to an energy (2.54 ev) far lower than the calculated energy gap (5.47 ev) that must be very close to the experimental one as showed in previous studies [18,19,25]. Although this phase possesses two types of clusters, it presents very little disorder, and no localized levels allowing electrons and holes to be trapped. The fact that Bouma and Blasse detected PL at room temperature with an excitation band of about 250 nm (4.96 ev) is probably not only due to the presence of isolated square TiO 5 pyramids like they suggested, but to the coexistence of the SiO 4 TiO 5 clusters and the fact that the excitation energy is very close to the band gap energy, so that there is no need of intermediate levels to assist the excitation. 5. Conclusions In this work, we presented a theoretical and experimental study based on DFT calculations and polymeric precursor method to understand the existence of room temperature PL emission in Li 2 TiSiO 5. The main conclusions are listed as follows: (i) The existence of PL emission is strongly related to the crystal structural disorder. (ii) To be PL, a compound must possess at least two types of differently charged clusters, creating a polarization, and some structural disorder leading to the presence of localized levels able to trap electrons and holes and favoring the radiative return to the ground state. (iii) The CB is clearly preponderantly made of the Ti (3d) states in both cases, with a weak Si contribution. (iv) In the crystalline powder, no PL emission is observed with our 488 nm excitation wavelength because it corresponds to an energy (2.54 ev) far lower than the calculated energy gap (5.47 ev). If it were sufficient to excite the system with an energy close to the band gap, every semiconducting compound would present PL behavior. Acknowledgements This work is supported by Brazilian Funding Agencies FAPESP, CAPES and CNPq. Computer facilities of the ÔLaboratório de Simulação MolecularÕ, Unesp, Bauru, Brazil, are also acknowledged. References [1] E.R. Leite, F.M. Pontes, E.J.H. Lee, R. Aguiar, E. Longo, D.S.L. Pontes, M.S.J. Nunes, H.R. Macedo, P.S. Pizani, F. Lanciotti, T.M. Boschi, J.A. Varela, C.A. Paskocimas, Appl. Phys. A Mater. Sci. Process. 74 (2002) 529. [2] P.S. Pizani, H.C. Basso, F. Lanciotti, T.M. Boschi, F.M. Pontes, E. Longo, E.R. Leite, Appl. Phys. Lett. 81 (2002) 253. [3] F.M. Pontes, E.R. Leite, E. Longo, J.A. Varela, P.S. Pizani, C.E.M. Campos, F. Lanciotti, Adv. Mater. Opt. Electron. 10 (2000) 81. [4] F. Lanciotti, P.S. Pizani, C.E.M. Campos, E.R. Leite, L.P.S. Santos, N.L.V. Carreño, E. Longo, Appl. Phys. A Mater. Sci. Process. 74 (2002) 787. [5] L.P.S. Santos, E.R. Leite, N.L.V. Carreño, E. Longo, C.A. Paskocimas, J.A. Varela, F. Lanciotti, C.E.M. Campos, P.S. Pizani, Appl. Phys. Lett. 78 (2001) 2148.

6 E. Orhan et al. / Chemical Physics Letters 398 (2004) [6] E.R. Leite, F.M. Pontes, E.C. Paris, C.A. Paskocimas, E.J.H. Lee, E. Longo, P.S. Pizani, J.A. Varela, V. Mastelaro, Adv. Mater. Opt. Electron. 10 (2000) 235. [7] F.M. Pontes, E. Longo, E.R. Leite, E.J.H. Lee, J.A. Varela, P.S. Pizani, C.E.M. Campos, F. Lanciotti, V. Mastelaro, C.D. Pinheiro, Mater. Chem. Phys. 77 (2003) 598. [8] B. Bouma, G. Blasse, J. Non-Cryst. Solids 56 (1995) 261. [9] A. Ziadi, G. Thiele, B. Elouadi, J. Solid State Chem. 109 (1994) 112. [10] F.M. Pontes, E. Longo, J.H. Rangel, M.I. Bernardi, E.R. Leite, J.A. Varela, Mater. Lett. 43 (2000) 249. [11] F.M. Pontes, J.H.G. Rangel, E.R. Leite, E. Longo, J.A. Varela, E.B. Araujo, J.A. Eiras, Thin Solid Films 366 (2000) 232. [12] R.I. Eglitis, E.A. Kotomin, G. Borstel, Eur. Phys. J. B 27 (2002) 483. [13] R. Leonelli, J.L. Brebner, Phys. Rev. B 33 (1986) [14] A.D. Becke, J. Chem. Phys. 98 (1993) [15] C. Lee, W. Yang, R.G. Parr, Phys. Rev. B 37 (1988) 785. [16] R. Dovesi, V.R. Saunders, C. Roetti, M. Causà, N.M. Harrison, R. Orlando, E. Aprà:, CRYSTAL98 UserÕs Manual, University of Torino, Torino, [17] A. Beltran, J.R. Sambrano, M. Calatayud, F.R. Sensato, J. Andres, Surf. Sci. 490 (2001) 116. [18] S. Lazaro, E. Longo, J.R. Sambrano, A. Beltran, Surf. Sci. 552 (2004) 149. [19] E. Longo, E. Orhan, F.M. Pontes, C.D. Pinheiro, E.R. Leite, J.A. Varela, P.S. Pizani, T.M. Boschi, F.J. Lanciotti, A. Beltran, J. Andrés, Phys. Rev. B 69 (2004) [20] M. Towler. Avaliable from: <www.tcm.phy.cam.ac.uk/dt26/ basis_sets>. [21] V. Albarici, private communication (2004). [22] A.J.H. Macke, J. Solid State Chem. 18 (1976) 337. [23] C.W. Ponader, H. Boek, J.E. Dickinson, J. Non-Cryst. Solids 201 (1996) 81. [24] M.C. Carotta et al., J. Appl. Phys. 94 (2003) [25] E. Heifets, R.I. Eglitis, E.A. Kotomin, J. Maier, G. Borstel, Phys. Rev. B 64 (2001), art. no

Crystal Structure of High Temperature Superconductors. Marie Nelson East Orange Campus High School NJIT Professor: Trevor Tyson

Crystal Structure of High Temperature Superconductors. Marie Nelson East Orange Campus High School NJIT Professor: Trevor Tyson Crystal Structure of High Temperature Superconductors Marie Nelson East Orange Campus High School NJIT Professor: Trevor Tyson Introduction History of Superconductors Superconductors are material which

More information

Lecture 2: Semiconductors: Introduction

Lecture 2: Semiconductors: Introduction Lecture 2: Semiconductors: Introduction Contents 1 Introduction 1 2 Band formation in semiconductors 2 3 Classification of semiconductors 5 4 Electron effective mass 10 1 Introduction Metals have electrical

More information

Phase Characterization of TiO 2 Powder by XRD and TEM

Phase Characterization of TiO 2 Powder by XRD and TEM Kasetsart J. (Nat. Sci.) 42 : 357-361 (28) Phase Characterization of TiO 2 Powder by XRD and TEM Kheamrutai Thamaphat 1 *, Pichet Limsuwan 1 and Boonlaer Ngotawornchai 2 ABSTRACT In this study, the commercial

More information

The study of structural and optical properties of TiO 2 :Tb thin films

The study of structural and optical properties of TiO 2 :Tb thin films Optica Applicata, Vol. XXXVII, No. 4, 2007 The study of structural and optical properties of TiO 2 :Tb thin films AGNIESZKA BORKOWSKA, JAROSLAW DOMARADZKI, DANUTA KACZMAREK, DAMIAN WOJCIESZAK Faculty of

More information

Types of Epitaxy. Homoepitaxy. Heteroepitaxy

Types of Epitaxy. Homoepitaxy. Heteroepitaxy Epitaxy Epitaxial Growth Epitaxy means the growth of a single crystal film on top of a crystalline substrate. For most thin film applications (hard and soft coatings, optical coatings, protective coatings)

More information

Introduction to X-Ray Powder Diffraction Data Analysis

Introduction to X-Ray Powder Diffraction Data Analysis Introduction to X-Ray Powder Diffraction Data Analysis Center for Materials Science and Engineering at MIT http://prism.mit.edu/xray An X-ray diffraction pattern is a plot of the intensity of X-rays scattered

More information

Matter, Materials, Crystal Structure and Bonding. Chris J. Pickard

Matter, Materials, Crystal Structure and Bonding. Chris J. Pickard Matter, Materials, Crystal Structure and Bonding Chris J. Pickard Why should a theorist care? Where the atoms are determines what they do Where the atoms can be determines what we can do Overview of Structure

More information

Preparation of ZnS and SnS Nanopowders by Modified SILAR Technique

Preparation of ZnS and SnS Nanopowders by Modified SILAR Technique Journal of Physical Sciences, Vol. 13, 009, 9-34 ISSN: 097-8791 : www.vidyasagar.ac.in/journal Preparation of ZnS and SnS Nanopowders by Modified SILAR Technique Department of Physics The University of

More information

Crystalline solids. A solid crystal consists of different atoms arranged in a periodic structure.

Crystalline solids. A solid crystal consists of different atoms arranged in a periodic structure. Crystalline solids A solid crystal consists of different atoms arranged in a periodic structure. Crystals can be formed via various bonding mechanisms: Ionic bonding Covalent bonding Metallic bonding Van

More information

X-ray thin-film measurement techniques

X-ray thin-film measurement techniques Technical articles X-ray thin-film measurement techniques II. Out-of-plane diffraction measurements Toru Mitsunaga* 1. Introduction A thin-film sample is two-dimensionally formed on the surface of a substrate,

More information

The study of deep-level emission center in ZnO films grown on c-al 2 O 3 substrates

The study of deep-level emission center in ZnO films grown on c-al 2 O 3 substrates The study of deep-level emission center in ZnO films grown on c-al 2 O 3 substrates Guotong Du Yuantao Zhang, Jinzhong Wang, Yongguo Cui (College of Electronic Science and Engineering, State Key Laboratory

More information

Plate waves in phononic crystals slabs

Plate waves in phononic crystals slabs Acoustics 8 Paris Plate waves in phononic crystals slabs J.-J. Chen and B. Bonello CNRS and Paris VI University, INSP - 14 rue de Lourmel, 7515 Paris, France chen99nju@gmail.com 41 Acoustics 8 Paris We

More information

X-Ray Diffraction HOW IT WORKS WHAT IT CAN AND WHAT IT CANNOT TELL US. Hanno zur Loye

X-Ray Diffraction HOW IT WORKS WHAT IT CAN AND WHAT IT CANNOT TELL US. Hanno zur Loye X-Ray Diffraction HOW IT WORKS WHAT IT CAN AND WHAT IT CANNOT TELL US Hanno zur Loye X-rays are electromagnetic radiation of wavelength about 1 Å (10-10 m), which is about the same size as an atom. The

More information

Exciton dissociation in solar cells:

Exciton dissociation in solar cells: Exciton dissociation in solar cells: Xiaoyang Zhu Department of Chemistry University of Minnesota, Minneapolis t (fs) 3h! E, k h! Pc Bi e - 1 Acknowledgement Organic semiconductors: Mutthias Muntwiler,

More information

Flame Tests & Electron Configuration

Flame Tests & Electron Configuration Flame Tests & Electron Configuration INTRODUCTION Many elements produce colors in the flame when heated. The origin of this phenomenon lies in the arrangement, or configuration of the electrons in the

More information

CHAPTER 10: INTERMOLECULAR FORCES: THE UNIQUENESS OF WATER Problems: 10.2, 10.6,10.15-10.33, 10.35-10.40, 10.56-10.60, 10.101-10.

CHAPTER 10: INTERMOLECULAR FORCES: THE UNIQUENESS OF WATER Problems: 10.2, 10.6,10.15-10.33, 10.35-10.40, 10.56-10.60, 10.101-10. CHAPTER 10: INTERMOLECULAR FORCES: THE UNIQUENESS OF WATER Problems: 10.2, 10.6,10.15-10.33, 10.35-10.40, 10.56-10.60, 10.101-10.102 10.1 INTERACTIONS BETWEEN IONS Ion-ion Interactions and Lattice Energy

More information

Luminescence study of structural changes induced by laser cutting in diamond films

Luminescence study of structural changes induced by laser cutting in diamond films Luminescence study of structural changes induced by laser cutting in diamond films A. Cremades and J. Piqueras Departamento de Fisica de Materiales, Facultad de Fisicas, Universidad Complutense, 28040

More information

Pathways of Li + ion mobility in superionic perovskites by ab initio simulations

Pathways of Li + ion mobility in superionic perovskites by ab initio simulations Pathways of Li + ion mobility in superionic perovskites by ab initio simulations Michele Catti Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Milano, Italy (catti@mater.unimib.it)

More information

The interaction of Cu(100)-Fe surfaces with oxygen studied with photoelectron spectroscopy. I

The interaction of Cu(100)-Fe surfaces with oxygen studied with photoelectron spectroscopy. I 5 The interaction of Cu(100)-Fe surfaces with oxygen studied with photoelectron spectroscopy. I Mg Kα excited photoemission. Abstract The oxidation of Cu(100)-Fe surfaces was studied using XPS. Surfaces

More information

Chemical Synthesis. Overview. Chemical Synthesis of Nanocrystals. Self-Assembly of Nanocrystals. Example: Cu 146 Se 73 (PPh 3 ) 30

Chemical Synthesis. Overview. Chemical Synthesis of Nanocrystals. Self-Assembly of Nanocrystals. Example: Cu 146 Se 73 (PPh 3 ) 30 Chemical Synthesis Spontaneous organization of molecules into stable, structurally well-defined aggregates at the nanometer length scale. Overview The 1-100 nm nanoscale length is in between traditional

More information

X-ray diffraction techniques for thin films

X-ray diffraction techniques for thin films X-ray diffraction techniques for thin films Rigaku Corporation Application Laboratory Takayuki Konya 1 Today s contents (PM) Introduction X-ray diffraction method Out-of-Plane In-Plane Pole figure Reciprocal

More information

MESOPOROUS MATERIALS FOR DRUG DELIVERY

MESOPOROUS MATERIALS FOR DRUG DELIVERY MESOPOROUS MATERIALS FOR DRUG DELIVERY A Quantum-Mechanical Simulation Massimo Delle Piane Dipartimento di Chimica Università di Torino massimo.dellepiane@unito.it MESOPOROUS SILICA MATERIALS FIRST SYNTHESIZED

More information

Applied Physics of solar energy conversion

Applied Physics of solar energy conversion Applied Physics of solar energy conversion Conventional solar cells, and how lazy thinking can slow you down Some new ideas *************************************************************** Our work on semiconductor

More information

Name period AP chemistry Unit 2 worksheet Practice problems

Name period AP chemistry Unit 2 worksheet Practice problems Name period AP chemistry Unit 2 worksheet Practice problems 1. What are the SI units for a. Wavelength of light b. frequency of light c. speed of light Meter hertz (s -1 ) m s -1 (m/s) 2. T/F (correct

More information

Cu Nanoparticles Enables Plasmonic-Improved Silicon Photovoltaic Devices

Cu Nanoparticles Enables Plasmonic-Improved Silicon Photovoltaic Devices Supporting Information to Cu Nanoparticles Enables Plasmonic-Improved Silicon Photovoltaic Devices Michele L. de Souza, a Paola Corio a and Alexandre G. Brolo, *b a Instituto de Química, Universidade de

More information

The Diode. Diode Operation

The Diode. Diode Operation The Diode The diode is a two terminal semiconductor device that allows current to flow in only one direction. It is constructed of a P and an N junction connected together. Diode Operation No current flows

More information

Physics 551: Solid State Physics F. J. Himpsel

Physics 551: Solid State Physics F. J. Himpsel Physics 551: Solid State Physics F. J. Himpsel Background Most of the objects around us are in the solid state. Today s technology relies heavily on new materials, electronics is predominantly solid state.

More information

Electronic Structure and the Periodic Table Learning Outcomes

Electronic Structure and the Periodic Table Learning Outcomes Electronic Structure and the Periodic Table Learning Outcomes (a) Electronic structure (i) Electromagnetic spectrum and associated calculations Electromagnetic radiation may be described in terms of waves.

More information

Glancing XRD and XRF for the Study of Texture Development in SmCo Based Films Sputtered Onto Silicon Substrates

Glancing XRD and XRF for the Study of Texture Development in SmCo Based Films Sputtered Onto Silicon Substrates 161 162 Glancing XRD and XRF for the Study of Texture Development in SmCo Based Films Sputtered Onto Silicon Substrates F. J. Cadieu*, I. Vander, Y. Rong, and R. W. Zuneska Physics Department Queens College

More information

3. What would you predict for the intensity and binding energy for the 3p orbital for that of sulfur?

3. What would you predict for the intensity and binding energy for the 3p orbital for that of sulfur? PSI AP Chemistry Periodic Trends MC Review Name Periodic Law and the Quantum Model Use the PES spectrum of Phosphorus below to answer questions 1-3. 1. Which peak corresponds to the 1s orbital? (A) 1.06

More information

Mg 2 FeH 6 -BASED NANOCOMPOSITES WITH HIGH CAPACITY OF HYDROGEN STORAGE PROCESSED BY REACTIVE MILLING

Mg 2 FeH 6 -BASED NANOCOMPOSITES WITH HIGH CAPACITY OF HYDROGEN STORAGE PROCESSED BY REACTIVE MILLING Mg 2 FeH 6 -BASED NANOCOMPOSITES WITH HIGH CAPACITY OF HYDROGEN STORAGE PROCESSED BY REACTIVE MILLING A. A. C. Asselli (1)*, C. S. Kiminami (2), A. M. Jorge Jr. (2), T.T. Ishikawa (2), and W. J. Botta

More information

Keywords: Planar waveguides, sol-gel technology, transmission electron microscopy

Keywords: Planar waveguides, sol-gel technology, transmission electron microscopy Structural and optical characterisation of planar waveguides obtained via Sol-Gel F. Rey-García, C. Gómez-Reino, M.T. Flores-Arias, G.F. De La Fuente, W. Assenmacher, W. Mader ABSTRACT Planar waveguides

More information

9.2 Network Covalent, Ionic, and Metallic Solids

9.2 Network Covalent, Ionic, and Metallic Solids 9.2 Network Covalent, Ionic, and Metallic Solids YOU ARE EXPECTED TO BE ABLE TO: Classify non-molecular solids as either network covalent solids, ionic solids, or metallic solids. Relate the physical properties

More information

Electronic transport properties of nano-scale Si films: an ab initio study

Electronic transport properties of nano-scale Si films: an ab initio study Electronic transport properties of nano-scale Si films: an ab initio study Jesse Maassen, Youqi Ke, Ferdows Zahid and Hong Guo Department of Physics, McGill University, Montreal, Canada Motivation (of

More information

Unit 3 Lesson 1 Minerals. Copyright Houghton Mifflin Harcourt Publishing Company

Unit 3 Lesson 1 Minerals. Copyright Houghton Mifflin Harcourt Publishing Company Animal, Vegetable, or Mineral? What do minerals have in common? Not all minerals are sparkling gems, but they all have certain characteristics in common. A mineral is a naturally occurring, inorganic solid

More information

Solid-State Physics: The Theory of Semiconductors (Ch. 10.6-10.8) SteveSekula, 30 March 2010 (created 29 March 2010)

Solid-State Physics: The Theory of Semiconductors (Ch. 10.6-10.8) SteveSekula, 30 March 2010 (created 29 March 2010) Modern Physics (PHY 3305) Lecture Notes Modern Physics (PHY 3305) Lecture Notes Solid-State Physics: The Theory of Semiconductors (Ch. 10.6-10.8) SteveSekula, 30 March 2010 (created 29 March 2010) Review

More information

Stress variations near surfaces in diamond-like amorphous carbon

Stress variations near surfaces in diamond-like amorphous carbon Journal of Non-Crystalline Solids 266±269 (2000) 760±764 www.elsevier.com/locate/jnoncrysol Stress variations near surfaces in diamond-like amorphous carbon M. Fyta a, P.C. Kelires a,b, * a Department

More information

phys4.17 Page 1 - under normal conditions (pressure, temperature) graphite is the stable phase of crystalline carbon

phys4.17 Page 1 - under normal conditions (pressure, temperature) graphite is the stable phase of crystalline carbon Covalent Crystals - covalent bonding by shared electrons in common orbitals (as in molecules) - covalent bonds lead to the strongest bound crystals, e.g. diamond in the tetrahedral structure determined

More information

Effect of surface area, pore volume and particle size of P25 titania on the phase transformation of anatase to rutile

Effect of surface area, pore volume and particle size of P25 titania on the phase transformation of anatase to rutile Indian Journal of Chemistry Vol. 48A, October 2009, pp. 1378-1382 Notes Effect of surface area, pore volume and particle size of P25 titania on the phase transformation of anatase to rutile K Joseph Antony

More information

Size effects. Lecture 6 OUTLINE

Size effects. Lecture 6 OUTLINE Size effects 1 MTX9100 Nanomaterials Lecture 6 OUTLINE -Why does size influence the material s properties? -How does size influence the material s performance? -Why are properties of nanoscale objects

More information

Periodic Table. inert gases. Columns: Similar Valence Structure. give up 1e - give up 2e - Oaccept 2e- accept 1e - give up 3e -

Periodic Table. inert gases. Columns: Similar Valence Structure. give up 1e - give up 2e - Oaccept 2e- accept 1e - give up 3e - Periodic Table give up 1e - give up 2e - give up 3e - H Li Be Na Mg K Ca Columns: Similar Valence Structure Sc Oaccept 2e- accept 1e - inert gases S Se F Cl Br He Ne Ar Kr Adapted from Fig. 2.6, Callister

More information

Crust: low density rocks. Mantle: high density rocks. Core: very high density metal. core

Crust: low density rocks. Mantle: high density rocks. Core: very high density metal. core Crust: low density rocks Mantle: high density rocks Core: very high density metal core mechanical) layering mechanical layers lithosphere: rigid & strong asthenosphere: plastic & weak mesosphere: plastic

More information

PRACTICE EXAM IV P202 SPRING 2004

PRACTICE EXAM IV P202 SPRING 2004 PRACTICE EXAM IV P202 SPRING 2004 1. In two separate double slit experiments, an interference pattern is observed on a screen. In the first experiment, violet light (λ = 754 nm) is used and a second-order

More information

3 - Atomic Absorption Spectroscopy

3 - Atomic Absorption Spectroscopy 3 - Atomic Absorption Spectroscopy Introduction Atomic-absorption (AA) spectroscopy uses the absorption of light to measure the concentration of gas-phase atoms. Since samples are usually liquids or solids,

More information

Scanning Near Field Optical Microscopy: Principle, Instrumentation and Applications

Scanning Near Field Optical Microscopy: Principle, Instrumentation and Applications Scanning Near Field Optical Microscopy: Principle, Instrumentation and Applications Saulius Marcinkevičius Optics, ICT, KTH 1 Outline Optical near field. Principle of scanning near field optical microscope

More information

Brazilian Journal of Physics, vol. 26, no. 1, March, 1996 239. Luis V. A. Scalvi and L. Oliveira

Brazilian Journal of Physics, vol. 26, no. 1, March, 1996 239. Luis V. A. Scalvi and L. Oliveira Brazilian Journal of Physics, vol. 26, no. 1, March, 1996 239 Light and Thermal Excitation of Depolarization Current in Indirect Bandgap Al x Ga 1;xAs Luis V. A. Scalvi and L. Oliveira Departamento de

More information

Unit 12 Practice Test

Unit 12 Practice Test Name: Class: Date: ID: A Unit 12 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1) A solid has a very high melting point, great hardness, and

More information

1 The water molecule and hydrogen bonds in water

1 The water molecule and hydrogen bonds in water The Physics and Chemistry of Water 1 The water molecule and hydrogen bonds in water Stoichiometric composition H 2 O the average lifetime of a molecule is 1 ms due to proton exchange (catalysed by acids

More information

Surface plasmon nanophotonics: optics below the diffraction limit

Surface plasmon nanophotonics: optics below the diffraction limit Surface plasmon nanophotonics: optics below the diffraction limit Albert Polman Center for nanophotonics FOM-Institute AMOLF, Amsterdam Jeroen Kalkman Hans Mertens Joan Penninkhof Rene de Waele Teun van

More information

Ultraviolet Spectroscopy

Ultraviolet Spectroscopy Ultraviolet Spectroscopy The wavelength of UV and visible light are substantially shorter than the wavelength of infrared radiation. The UV spectrum ranges from 100 to 400 nm. A UV-Vis spectrophotometer

More information

JOURNAL INTEGRATED CIRCUITS AND SYSTEMS, VOL 1, NO. 3, JULY 2006. 39

JOURNAL INTEGRATED CIRCUITS AND SYSTEMS, VOL 1, NO. 3, JULY 2006. 39 JOURNAL INTEGRATED CIRCUITS AND SYSTEMS, VOL 1, NO. 3, JULY 2006. 39 Self-Assembled Polystyrene Micro-Spheres Applied for Photonic Crystals and Templates Fabrication Daniel S. Raimundo 1, Francisco J.

More information

Optical Hyperdoping: Transforming Semiconductor Band Structure for Solar Energy Harvesting

Optical Hyperdoping: Transforming Semiconductor Band Structure for Solar Energy Harvesting Optical Hyperdoping: Transforming Semiconductor Band Structure for Solar Energy Harvesting 3G Solar Technologies Multidisciplinary Workshop MRS Spring Meeting San Francisco, CA, 5 April 2010 Michael P.

More information

X-ray photoelectron. Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 δ and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 δ before and after thermal treatment and permeation test

X-ray photoelectron. Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 δ and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 δ before and after thermal treatment and permeation test study on Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 δ and La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 δ before and after thermal treatment and permeation test Patrizia Rosa 1 1 Dipartimenti di Fisica Università degli Studi di

More information

IUCLID 5 COMPOSITION AND ANALYSIS GUIDANCE DOCUMENT: IRON ORES, AGGLOMERATES [EINECS NUMBER 265 996 3, CAS NUMBER 65996 65 8] IRON ORE PELLETS

IUCLID 5 COMPOSITION AND ANALYSIS GUIDANCE DOCUMENT: IRON ORES, AGGLOMERATES [EINECS NUMBER 265 996 3, CAS NUMBER 65996 65 8] IRON ORE PELLETS IUCLID 5 COMPOSITION AND ANALYSIS GUIDANCE DOCUMENT: IRON ORES, AGGLOMERATES [EINECS NUMBER 265 996 3, CAS NUMBER 65996 65 8] IRON ORE PELLETS INTRODUCTION Each REACH registrant is required to file its

More information

DO PHYSICS ONLINE FROM QUANTA TO QUARKS QUANTUM (WAVE) MECHANICS

DO PHYSICS ONLINE FROM QUANTA TO QUARKS QUANTUM (WAVE) MECHANICS DO PHYSICS ONLINE FROM QUANTA TO QUARKS QUANTUM (WAVE) MECHANICS Quantum Mechanics or wave mechanics is the best mathematical theory used today to describe and predict the behaviour of particles and waves.

More information

6.5 Periodic Variations in Element Properties

6.5 Periodic Variations in Element Properties 324 Chapter 6 Electronic Structure and Periodic Properties of Elements 6.5 Periodic Variations in Element Properties By the end of this section, you will be able to: Describe and explain the observed trends

More information

The Physics of Energy sources Renewable sources of energy. Solar Energy

The Physics of Energy sources Renewable sources of energy. Solar Energy The Physics of Energy sources Renewable sources of energy Solar Energy B. Maffei Bruno.maffei@manchester.ac.uk Renewable sources 1 Solar power! There are basically two ways of using directly the radiative

More information

X Ray Flourescence (XRF)

X Ray Flourescence (XRF) X Ray Flourescence (XRF) Aspiring Geologist XRF Technique XRF is a rapid, relatively non destructive process that produces chemical analysis of rocks, minerals, sediments, fluids, and soils It s purpose

More information

Anharmonicity and Weak Mode Assignment in La 2 x Sr x CuO 4 with Oxygen Isotopic Substitution

Anharmonicity and Weak Mode Assignment in La 2 x Sr x CuO 4 with Oxygen Isotopic Substitution Vol. 111 (2007) ACTA PHYSICA POLONICA A No. 1 Proceedings of the Symposium K: Complex Oxide Materials for New Technologies of E-MRS Fall Meeting 2006, Warsaw, September 4 8, 2006 Anharmonicity and Weak

More information

Supporting Information

Supporting Information Supporting Information Simple and Rapid Synthesis of Ultrathin Gold Nanowires, Their Self-Assembly and Application in Surface-Enhanced Raman Scattering Huajun Feng, a Yanmei Yang, a Yumeng You, b Gongping

More information

Chem 106 Thursday Feb. 3, 2011

Chem 106 Thursday Feb. 3, 2011 Chem 106 Thursday Feb. 3, 2011 Chapter 13: -The Chemistry of Solids -Phase Diagrams - (no Born-Haber cycle) 2/3/2011 1 Approx surface area (Å 2 ) 253 258 Which C 5 H 12 alkane do you think has the highest

More information

Multiple Choice (4 points each): Answer on blue form; be sure to code in your name and ID.

Multiple Choice (4 points each): Answer on blue form; be sure to code in your name and ID. Multiple Choice (4 points each): Answer on blue form; be sure to code in your name and ID. 1. The Bohr model of the atom works reasonably well in the calculation of energy levels in hydrogen. What other

More information

TiO 2. : A New Kind of Water Treatment. Registered charity number 207890

TiO 2. : A New Kind of Water Treatment.  Registered charity number 207890 TiO 2 : A New Kind of Water Treatment www.rsc.org/learn-chemistry Registered charity number 207890 3: A new kind of water treatment What is solar disinfection with titanium dioxide and how does it work?

More information

Chem 1A Exam 2 Review Problems

Chem 1A Exam 2 Review Problems Chem 1A Exam 2 Review Problems 1. At 0.967 atm, the height of mercury in a barometer is 0.735 m. If the mercury were replaced with water, what height of water (in meters) would be supported at this pressure?

More information

Luminescence and Optical Properties of Tm 3+ :TeO 2 - ZnO-TiO 2 Glasses for Fiber Optic Applications

Luminescence and Optical Properties of Tm 3+ :TeO 2 - ZnO-TiO 2 Glasses for Fiber Optic Applications Luminescence and Optical Properties of Tm + :TeO - ZnO-TiO Glasses for Fiber Optic Applications İdris Kabalcı 1, Turgay Tay Tuğba Duran, Mustafa Özdemir, Gönül Özen 4 1 Department of Physics Education,,

More information

Comparison of approximations to the transition rate in the DDHMS preequilibrium model

Comparison of approximations to the transition rate in the DDHMS preequilibrium model EPJ Web of Conferences 69, 0 00 24 (204) DOI: 0.05/ epjconf/ 2046900024 C Owned by the authors, published by EDP Sciences, 204 Comparison of approximations to the transition rate in the DDHMS preequilibrium

More information

h e l p s y o u C O N T R O L

h e l p s y o u C O N T R O L contamination analysis for compound semiconductors ANALYTICAL SERVICES B u r i e d d e f e c t s, E v a n s A n a l y t i c a l g r o u p h e l p s y o u C O N T R O L C O N T A M I N A T I O N Contamination

More information

The Periodic Table: Periodic trends

The Periodic Table: Periodic trends Unit 1 The Periodic Table: Periodic trends There are over one hundred different chemical elements. Some of these elements are familiar to you such as hydrogen, oxygen, nitrogen and carbon. Each one has

More information

B) atomic number C) both the solid and the liquid phase D) Au C) Sn, Si, C A) metal C) O, S, Se C) In D) tin D) methane D) bismuth B) Group 2 metal

B) atomic number C) both the solid and the liquid phase D) Au C) Sn, Si, C A) metal C) O, S, Se C) In D) tin D) methane D) bismuth B) Group 2 metal 1. The elements on the Periodic Table are arranged in order of increasing A) atomic mass B) atomic number C) molar mass D) oxidation number 2. Which list of elements consists of a metal, a metalloid, and

More information

Applications of New, High Intensity X-Ray Optics - Normal and thin film diffraction using a parabolic, multilayer mirror

Applications of New, High Intensity X-Ray Optics - Normal and thin film diffraction using a parabolic, multilayer mirror Applications of New, High Intensity X-Ray Optics - Normal and thin film diffraction using a parabolic, multilayer mirror Stephen B. Robie scintag, Inc. 10040 Bubb Road Cupertino, CA 95014 Abstract Corundum

More information

Untitled Document. 1. Which of the following best describes an atom? 4. Which statement best describes the density of an atom s nucleus?

Untitled Document. 1. Which of the following best describes an atom? 4. Which statement best describes the density of an atom s nucleus? Name: Date: 1. Which of the following best describes an atom? A. protons and electrons grouped together in a random pattern B. protons and electrons grouped together in an alternating pattern C. a core

More information

TiO 2. : Manufacture of Titanium Dioxide. www.rsc.org/learn-chemistry Registered charity number 207890

TiO 2. : Manufacture of Titanium Dioxide. www.rsc.org/learn-chemistry Registered charity number 207890 TiO 2 : Manufacture of Titanium Dioxide www.rsc.org/learn-chemistry Registered charity number 207890 5: Manufacture of titanium dioxide Titanium dioxide has many uses. It is now the common white pigment

More information

AN INNOVATED LABORATORY XAFS APPARATUS

AN INNOVATED LABORATORY XAFS APPARATUS Copyright (c)jcpds-international Centre for Diffraction Data 2002, Advances in X-ray Analysis, Volume 45. 397 AN INNOVATED LABORATORY XAFS APPARATUS TAGUCHI Takeyoshi XRD Division, Rigaku Corporation HARADA

More information

Photoinduced volume change in chalcogenide glasses

Photoinduced volume change in chalcogenide glasses Photoinduced volume change in chalcogenide glasses (Ph.D. thesis points) Rozália Lukács Budapest University of Technology and Economics Department of Theoretical Physics Supervisor: Dr. Sándor Kugler 2010

More information

X-ray Diffraction (XRD)

X-ray Diffraction (XRD) X-ray Diffraction (XRD) 1.0 What is X-ray Diffraction 2.0 Basics of Crystallography 3.0 Production of X-rays 4.0 Applications of XRD 5.0 Instrumental Sources of Error 6.0 Conclusions Bragg s Law n l =2dsinq

More information

Lara Lama laral@kth.se. Axel Nordström axenor@kth.se. Supervisors: Jan Linnros Ilya Sychugov

Lara Lama laral@kth.se. Axel Nordström axenor@kth.se. Supervisors: Jan Linnros Ilya Sychugov Photoluminescence and AFM characterization of silicon nanocrystals prepared by low-temperature plasma enhanced chemical vapour deposition and annealing Lara Lama laral@kth.se Axel Nordström axenor@kth.se

More information

A metal-free polymeric photocatalyst for hydrogen production from water under visible light

A metal-free polymeric photocatalyst for hydrogen production from water under visible light A metal-free polymeric photocatalyst for hydrogen production from water under visible light Xinchen Wang, Kazuhiko Maeda, Arne Thomas, Kazuhiro Takanabe, Gang Xin, Johan M. Carlsson, Kazunari Domen, Markus

More information

Preface Light Microscopy X-ray Diffraction Methods

Preface Light Microscopy X-ray Diffraction Methods Preface xi 1 Light Microscopy 1 1.1 Optical Principles 1 1.1.1 Image Formation 1 1.1.2 Resolution 3 1.1.3 Depth of Field 5 1.1.4 Aberrations 6 1.2 Instrumentation 8 1.2.1 Illumination System 9 1.2.2 Objective

More information

emission of light from atoms discrete line spectra - energy levels, Franck-Hertz experiment

emission of light from atoms discrete line spectra - energy levels, Franck-Hertz experiment Introduction Until the early 20 th century physicists used to explain the phenomena in the physical world around them using theories such a mechanics, electromagnetism, thermodynamics and statistical physics

More information

Chapter 8 Molecules. Some molecular bonds involve sharing of electrons between atoms. These are covalent bonds.

Chapter 8 Molecules. Some molecular bonds involve sharing of electrons between atoms. These are covalent bonds. Chapter 8 Molecules (We have only three days for chapter 8!) 8.1 The Molecular Bond A molecule is an electrically neutral group of atoms held together strongly enough to behave as a single particle. A

More information

Developments in Photoluminescence Characterisation for Silicon PV

Developments in Photoluminescence Characterisation for Silicon PV Developments in Photoluminescence Characterisation for Silicon PV School of Photovoltaic and Solar Energy Engineering Bernhard Mitchell 1, Thorsten Trupke 1,2, Jürgen W. Weber 2, Johannes Greulich 3, Matthias

More information

Photovoltaic and Photoelectrochemical Solar Cells

Photovoltaic and Photoelectrochemical Solar Cells Photovoltaic and Photoelectrochemical Solar Cells EDDIE FOROUZAN, PH.D. ARTIN ENGINEERING AND CONSULTING GROUP, INC. 7933 SILVERTON AVE. #715 SAN DIEGO, CA 92128 PSES San Diego Chapter 2012-02-10 History

More information

Back to Basics Fundamentals of Polymer Analysis

Back to Basics Fundamentals of Polymer Analysis Back to Basics Fundamentals of Polymer Analysis Using Infrared & Raman Spectroscopy Molecular Spectroscopy in the Polymer Manufacturing Process Process NIR NIR Production Receiving Shipping QC R&D Routine

More information

Laser sintering of greens compacts of MoSi 2

Laser sintering of greens compacts of MoSi 2 Laser sintering of greens compacts of MoSi 2 G. de Vasconcelos 1, R. Cesar Maia 2, C.A.A.Cairo 3, R. Riva 2, N.A.S.Rodrigues 2, F.C.L.Mello 3 Instituto de Estudos Avançados 1, Instituto Tecnológico de

More information

GEOL 2311 Midquarter Exam I Name Crystal Chemistry Score: / 100

GEOL 2311 Midquarter Exam I Name Crystal Chemistry Score: / 100 GEOL 2311 Midquarter Exam I Name Crystal Chemistry Score: / 100 1. Chose a subdiscipline of geology and describe how mineralogy plays a central role in that field. (2 pts) Looking for reasonable answers

More information

CHAPTER 6 Chemical Bonding

CHAPTER 6 Chemical Bonding CHAPTER 6 Chemical Bonding SECTION 1 Introduction to Chemical Bonding OBJECTIVES 1. Define Chemical bond. 2. Explain why most atoms form chemical bonds. 3. Describe ionic and covalent bonding.. 4. Explain

More information

LAUE DIFFRACTION INTRODUCTION CHARACTERISTICS X RAYS BREMSSTRAHLUNG

LAUE DIFFRACTION INTRODUCTION CHARACTERISTICS X RAYS BREMSSTRAHLUNG LAUE DIFFRACTION INTRODUCTION X-rays are electromagnetic radiations that originate outside the nucleus. There are two major processes for X-ray production which are quite different and which lead to different

More information

Chapter 8. Low energy ion scattering study of Fe 4 N on Cu(100)

Chapter 8. Low energy ion scattering study of Fe 4 N on Cu(100) Low energy ion scattering study of 4 on Cu(1) Chapter 8. Low energy ion scattering study of 4 on Cu(1) 8.1. Introduction For a better understanding of the reconstructed 4 surfaces one would like to know

More information

SOME TOUGH COLLEGE PROBLEMS! .. : 4. How many electrons should be shown in the Lewis dot structure for carbon monoxide? N O O

SOME TOUGH COLLEGE PROBLEMS! .. : 4. How many electrons should be shown in the Lewis dot structure for carbon monoxide? N O O SME TUGH CLLEGE PRBLEMS! LEWIS DT STRUCTURES 1. An acceptable Lewis dot structure for 2 is (A) (B) (C) 2. Which molecule contains one unshared pair of valence electrons? (A) H 2 (B) H 3 (C) CH 4 acl 3.

More information

Electrons in Atoms & Periodic Table Chapter 13 & 14 Assignment & Problem Set

Electrons in Atoms & Periodic Table Chapter 13 & 14 Assignment & Problem Set Electrons in Atoms & Periodic Table Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. Electrons in Atoms & Periodic Table 2 Study Guide: Things You

More information

Synthesis and Crystal Structure of Na 2 TiO 3

Synthesis and Crystal Structure of Na 2 TiO 3 27 卷 5 期 结 构 化 学 (JIEGOU HUAXUE) Vol. 27, No.5 2008. 5 Chinese J. Struct. Chem. 553~557 Synthesis and Crystal Structure of Na 2 TiO 3 MAO Shao-Yu 1 REN Xiao-Xia ZHOU Zhao-Hui (State Key Laboratory for

More information

S block elements p block elements and chemical bonding -1

S block elements p block elements and chemical bonding -1 S block elements p block elements and chemical bonding -1 1.Group I elements do not occur free (native state) in the nature because a. They are unstable b. Their compounds with other elements are highly

More information

Features of the formation of hydrogen bonds in solutions of polysaccharides during their use in various industrial processes. V.Mank a, O.

Features of the formation of hydrogen bonds in solutions of polysaccharides during their use in various industrial processes. V.Mank a, O. Features of the formation of hydrogen bonds in solutions of polysaccharides during their use in various industrial processes. V.Mank a, O. Melnyk b a National University of life and environmental sciences

More information

Rapid structure determination of disordered materials: study of GeSe 2 glass

Rapid structure determination of disordered materials: study of GeSe 2 glass Solid State Communications 129 (2004) 239 243 www.elsevier.com/locate/ssc Rapid structure determination of disordered materials: study of GeSe 2 glass V. Petkov a, *, D. Qadir a, S.D. Shastri b a Department

More information

Electrical Conductivity

Electrical Conductivity Advanced Materials Science - Lab Intermediate Physics University of Ulm Solid State Physics Department Electrical Conductivity Translated by Michael-Stefan Rill January 20, 2003 CONTENTS 1 Contents 1 Introduction

More information

Lecture 22 The Acid-Base Character of Oxides and Hydroxides in Aqueous Solution

Lecture 22 The Acid-Base Character of Oxides and Hydroxides in Aqueous Solution 2P32 Principles of Inorganic Chemistry Dr. M. Pilkington Lecture 22 The Acid-Base Character of Oxides and Hydroxides in Aqueous Solution Oxides; acidic, basic, amphoteric Classification of oxides - oxide

More information

The Advanced Placement Examination in Chemistry. Part I Multiple Choice Questions Part II Free Response Questions Selected Questions from1970 to 2010

The Advanced Placement Examination in Chemistry. Part I Multiple Choice Questions Part II Free Response Questions Selected Questions from1970 to 2010 The Advanced Placement Examination in Chemistry Part I Multiple Choice Questions Part II Free Response Questions Selected Questions from1970 to 2010 Atomic Theory and Periodicity Part I 1984 1. Which of

More information

Al 2 O 3, Its Different Molecular Structures, Atomic Layer Deposition, and Dielectrics

Al 2 O 3, Its Different Molecular Structures, Atomic Layer Deposition, and Dielectrics Al 2 O 3, Its Different Molecular Structures, Atomic Layer Deposition, and Dielectrics Mark Imus Douglas Sisk, Ph.D., Mentor Marian High School RET Program University of Notre Dame Project Proposal Tunneling

More information

Spatially separated excitons in 2D and 1D

Spatially separated excitons in 2D and 1D Spatially separated excitons in 2D and 1D David Abergel March 10th, 2015 D.S.L. Abergel 3/10/15 1 / 24 Outline 1 Introduction 2 Spatially separated excitons in 2D The role of disorder 3 Spatially separated

More information

Experiment #5: Qualitative Absorption Spectroscopy

Experiment #5: Qualitative Absorption Spectroscopy Experiment #5: Qualitative Absorption Spectroscopy One of the most important areas in the field of analytical chemistry is that of spectroscopy. In general terms, spectroscopy deals with the interactions

More information