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** 4.14. Calculated electronic structure **

** Electronic structure calculations **

** Electronic structure calculations experimental vs theoretical **

Theoretical Computational Electronic structure calculations/ basic theory 6 2 4 33 [Pg.140]

G. A. Segal, S emiempirical Methods of Electronic Structure Calculation, Modem Theoretical Chemist, Vols. 7 and 8, Plenum Publishing, New York, 1977. [Pg.98]

Abstract Theoretical investigations of ionic liquids are reviewed. Three main categories are discussed, i.e., static quantum chemical calculations (electronic structure methods), traditional molecular dynamics simulations and first-principles molecular dynamics simulations. Simple models are reviewed in brief. [Pg.213]

Silatranes are known since more than 50 years [287, 288] but are stiU fascinating molecules in the focus of an ongoing scientific interest. Fluoro-substituted quasisilatranes have been synthesized [214, 289-291]. Experimental and theoretically calculated electron density distribution functions in the crystal structure of 84 have been investigated [214]. Properties of chemical bonding in silatranes have also been studied in 1-hydrosilatrane [218] and 1-fluorosilatrane [219]. [Pg.70]

As described in Section 1, there exist many theoretical approaches to calculating electronic structure of solids, and most of them have also been applied to lanthanides. In this section, we shall briefly overview some of the most widely used, focusing however on the SIC-LSD, in both full and local implementations, as this is the method of choice for most of the calculations reported in this chapter. The simplest approach to deal with the f electrons is to treat them like any other electron, that is, as itinerant band states. Hence, we start our review of modem methods with a brief account of the standard LDA and its spin-polarized version, namely the LSD approximation. We also comment on the use of LSD in the cases, where one restricts the variational space by fixing the assumed number of f electrons to be in the (chemically inert) core ( f-core approach). Following this, we then briefly overview the basics of other, more advanced, electronic stmcture methods mentioned in Section 1, as opposed to a more elaborate description of the SIC-LSD method. [Pg.15]

Chapter 1, Computational Models and Model Chemistries, provides an overview of the computational chemistry field and where electronic structure theory fits within it. It also discusses the general theoretical methods and procedures employed in electronic structure calculations (a more detailed treatment of the underlying quantum mechanical theory is given in Appendix A). [Pg.316]

Part 1, Essential Concepts Techniques, introduces computational chemistry and the principal sorts of predictions which can be made using electronic structure theory. It presents both the underlying theoretical and philosophical approach to electronic structure calculations taken by this book and the fundamental procedures and techniques for performing them. [Pg.316]

The first empirical and qualitative approach to the electronic structure of thiazole appeared in 1931 in a paper entitled Aspects of the chemistry of the thiazole group (115). In this historical review. Hunter showed the technical importance of the group, especially of the benzothiazole derivatives, and correlated the observed reactivity with the mobility of the electronic system. In 1943, Jensen et al. (116) explained the low value observed for the dipole moment of thiazole (1.64D in benzene) by the small contribution of the polar-limiting structures and thus by an essentially dienic character of the v system of thiazole. The first theoretical calculation of the electronic structure of thiazole. benzothiazole, and their methyl derivatives was performed by Pullman and Metzger using the Huckel method (5, 6, 8). [Pg.26]

In this chapter, we will consider the other half of a model chemistry definition the theoretical method used to model the molecular system. This chapter will serve as an introductory survey of the major classes of electronic structure calculations. The examples and exercises will compare the strengths and weaknesses of various specific methods in more detail. The final section of the chapter considers the CPU, memory and disk resource requirements of the various methods. [Pg.111]

The theoreticed approach that complements the nonideal plasma is derived from the concepts of solid-state physics. Instead of considering the thermal generation of vapor-phase species, one starts with a fixed ionic structure and attempts to calculate electronic structure and properties. Various theoretical models differ with respect to the assumed structure and the Hamiltonian used to represent the electronic energy. [Pg.43]

Whereas the proton (H ) can be considered the ultimate Bronsted acid (having no electron), the helium dication (He ) is an even stronger, doubly electron-deficient eleetron aceeptor. In a theoretical, calculational study we found that the helionitronium trication (NOaHe" ) has a minimum structure isoelectronic and isostructural [Pg.200]

** 4.14. Calculated electronic structure **

** Electronic structure calculations **

** Electronic structure calculations experimental vs theoretical **

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