Atoms, Molecules and Solids

2017 ◽  
Author(s):  
Nicholas Manton ◽  
Nicholas Mee
Keyword(s):  
Band Structure ◽  
Atomic Structure ◽  
Orbital Theory ◽  
Solid State Physics ◽  
Band Theory ◽  
Physics First ◽  
Caesium Chloride ◽  
Introductory Overview ◽  
Hückel Theory ◽  
Bloch’S Theorem

Chapter 9 presents an introductory overview of quantum chemistry and solid state physics. First, the Periodic Table is examined in terms of atomic structure, electron orbitals and the shell model. Simple polar and non-polar molecules are considered in terms of the overlap of atomic orbitals which gives rise to covalent bonding between atoms. Hückel theory is used to analyse the electronic structure of benzene and polyene molecules. These ideas are extended to periodic solids. Bloch’s theorem is used to explain their band structure in terms of molecular orbital theory. Band theory provides an explanation of the distinctions between metals, semi-conductors and insulators. Caesium chloride is used to illustrate how the band structure and properties of an ionic compound arise from its atomic structure. Metals are discussed, with emphasis on copper as an illustrative example, and the significance of the Fermi surface is explained. Ferromagnetism is considered in the transition metals.

The Chemical Bond Across the Periodic Table: Part 1 – First Row and Simple Metals

2020 ◽  
Author(s):  
Gabriel Freire Sanzovo Fernandes ◽  
Leonardo dos Anjos Cunha ◽  
Francisco Bolivar Correto Machado ◽  
Luiz Ferrão
Keyword(s):  
Physical Chemistry ◽  
Chemical Bond ◽  
Materials Science ◽  
Chemical Elements ◽  
Orbital Theory ◽  
Solid State Physics ◽  
Band Theory ◽  
Van Der Waals Clusters ◽  
Earth Systems ◽  
Chemical Content

<p>Chemical bond plays a central role in the description of the physicochemical properties of molecules and solids and it is essential to several fields in science and engineering, governing the material’s mechanical, electrical, catalytic and optoelectronic properties, among others. Due to this indisputable importance, a proper description of chemical bond is needed, commonly obtained through solving the Schrödinger equation of the system with either molecular orbital theory (molecules) or band theory (solids). However, connecting these seemingly different concepts is not a straightforward task for students and there is a gap in the available textbooks concerning this subject. This work presents a chemical content to be added in the physical chemistry undergraduate courses, in which the framework of molecular orbitals was used to qualitatively explain the standard state of the chemical elements and some properties of the resulting material, such as gas or crystalline solids. Here in Part 1, we were able to show the transition from Van der Waals clusters to metal in alkali and alkaline earth systems. In Part 2 and 3 of this three-part work, the present framework is applied to main group elements and transition metals. The original content discussed here can be adapted and incorporated in undergraduate and graduate physical chemistry and/or materials science textbooks and also serves as a conceptual guide to subsequent disciplines such as quantum chemistry, quantum mechanics and solid-state physics.</p>

The Chemical Bond Across the Periodic Table: Part 1 – First Row and Simple Metals

2020 ◽  
Author(s):  
Gabriel Freire Sanzovo Fernandes ◽  
Leonardo dos Anjos Cunha ◽  
Francisco Bolivar Correto Machado ◽  
Luiz Ferrão
Keyword(s):  
Physical Chemistry ◽  
Chemical Bond ◽  
Materials Science ◽  
Chemical Elements ◽  
Orbital Theory ◽  
Solid State Physics ◽  
Band Theory ◽  
Van Der Waals Clusters ◽  
Earth Systems ◽  
Chemical Content

<p>Chemical bond plays a central role in the description of the physicochemical properties of molecules and solids and it is essential to several fields in science and engineering, governing the material’s mechanical, electrical, catalytic and optoelectronic properties, among others. Due to this indisputable importance, a proper description of chemical bond is needed, commonly obtained through solving the Schrödinger equation of the system with either molecular orbital theory (molecules) or band theory (solids). However, connecting these seemingly different concepts is not a straightforward task for students and there is a gap in the available textbooks concerning this subject. This work presents a chemical content to be added in the physical chemistry undergraduate courses, in which the framework of molecular orbitals was used to qualitatively explain the standard state of the chemical elements and some properties of the resulting material, such as gas or crystalline solids. Here in Part 1, we were able to show the transition from Van der Waals clusters to metal in alkali and alkaline earth systems. In Part 2 and 3 of this three-part work, the present framework is applied to main group elements and transition metals. The original content discussed here can be adapted and incorporated in undergraduate and graduate physical chemistry and/or materials science textbooks and also serves as a conceptual guide to subsequent disciplines such as quantum chemistry, quantum mechanics and solid-state physics.</p>

Photocatalytic reactivity of {121} and {211} facets of brookite TiO2 crystals

2015 ◽  
Vol 3 (5) ◽  
pp. 2331-2337 ◽  
Author(s):  
Ming Zhao ◽  
Hua Xu ◽  
Hungru Chen ◽  
Shuxin Ouyang ◽  
Naoto Umezawa ◽  
...  
Keyword(s):  
Band Structure ◽  
Atomic Structure ◽  
Photocatalytic Oxidation ◽  
Electronic Band Structure ◽  
Photocatalytic Reduction ◽  
Electronic Band

Combining the surface atomic structure and electronic band structure, it is suggested that, for brookite TiO2, the {121} surface is beneficial for photocatalytic oxidation and the {211} surface can facilitate photocatalytic reduction.

Band Structure Theory for Extended Systems

2020 ◽  
pp. 246-278
Author(s):  
Jochen Autschbach
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Electron Gas ◽  
Three Dimensional ◽  
Structure Theory ◽  
Crystal Lattices ◽  
Hückel Theory ◽  
Periodic Linear ◽  
Crystal Orbitals ◽  
Dimensional Crystal

The electronic structure of infinite periodic systems (crystals) is treated with band structure theory, replacing molecular orbitals by crystal orbitals. The chapter starts out by introducing the electron gas and definitions of the Fermi momentum, the Fermi energy, and the density of states (DOS). A periodic linear combination of atomic orbitals (LCAO) type treatment of an infinite periodic system is facilitated by the construction of Bloch functions. The notions of energy band and band gap are discussed with band structure concepts, using the approximations made in Huckel theory (chapter 12). One, two, and three-dimensional crystal lattices and the associated reciprocal lattices are introduced. The band structures of sodium metal, boron nitride, silicon, and graphite, are discussed as examples of metals, insulators, semi-conductors, and semi-metals, respectively. The chapter concludes with a brief discussion of the projected DOS and measures to determine bonding or antibonding interactions between atoms in a crystal.

On the Band Structure of Möbius Polymers

1983 ◽  
Vol 38 (8) ◽  
pp. 909-915
Author(s):  
Oskar E. Polansky
Keyword(s):  
Band Structure ◽  
Extended Huckel Theory ◽  
Extended Hückel ◽  
Hückel Theory ◽  
Cylindrical Form ◽  
Extended Hückel Theory

Abstract The π-band structure of Möbius polymers (M) is compared with that of the open strip (F) and the cylindrical form (R) of the polymer considered. Under certain conditions, the bands of all these forms coincide. This is to be expected also for the σ-bands within the framework of extended Hückel theory.

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