The abinitio model potential method. Cowan–Griffin relativistic core potentials and valence basis sets from Li (Z = 3) to La (Z = 57)

1992 ◽  
Vol 70 (2) ◽  
pp. 409-415 ◽  
Author(s):  
Zoila Barandiarán ◽  
Luis Seijo
Keyword(s):  
Mass Velocity ◽  
Alkaline Earth ◽  
Relativistic Effects ◽  
Potential Method ◽  
Model Potential ◽  
Basis Sets ◽  
Relativistic Model ◽  
Model Potentials ◽  
Valence Basis Sets ◽  
Potential Basis

A comprehensive tabulation of Cowan–Griffin relativistic abinitio core model potentials and valence basis sets corresponding to the Cowan–Griffin abinitio model potential method is presented. It includes those for the elements from Li (Z = 3) to La (Z = 57), the alkaline M+ and alkaline earth M2+ cations, and for the halogen X− anions. Molecular results are presented in order to test the potentials and basis sets and to estimate the extent of the mass–velocity and Darwin relativistic effects considered within the method, which lie within the expected margins. Keywords: relativistic, model potential, effective core potential, basis sets, abinitio.

1994 Polanyi Award Lecture Concept of active electrons in chemistry

1995 ◽  
Vol 73 (5) ◽  
pp. 619-628 ◽  
Author(s):  
Sigeru Huzinaga
Keyword(s):  
Solid State ◽  
Relativistic Effects ◽  
Potential Method ◽  
Model Potential ◽  
Computational Method ◽  
Computational Accuracy ◽  
The Core ◽  
Way Of Thinking

The notion of division between active and dormant electrons has been well received and widely used in the chemists' way of thinking. The core–valence separation in atoms is the best-known example. This paper describes a theoretical and computational method called the model potential method, which deals only with active electrons in molecular and solid state calculations. The method is capable of reaching computational accuracy of testing the validity of the separation of active and dormant electrons in individual cases. Keywords: separability of electrons, model potential method, valence orbitals, relativistic effects.

Theoretical study of the deformation densities of d electrons in K2[PdCl6] and K2[PtCl6] crystals

1996 ◽  
Vol 52 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Y. Sakai ◽  
T. Oshibe ◽  
E. Miyoshi
Keyword(s):  
Theoretical Calculations ◽  
Diffraction Method ◽  
Relativistic Effects ◽  
Potential Method ◽  
Model Potential ◽  
X Ray Diffraction ◽  
Hartree Fock ◽  
Density Maps ◽  
Electron Deficiency ◽  
Configuration Interaction Calculations

Aspherical distributions of the d electrons in dipotassium palladium hexachloride, K2[PdCl6], and dipotassium platinum hexachloride, K2[PtCl6], crystals were analyzed by theoretical calculations. Hartree–Fock and configuration interaction calculations were performed for [PdCl6]2− and [PtCl6]2− with and without taking into account the Madelung potentials, using a model potential method. The major relativistic effects were incorporated in the model potentials for Pd and Pt. The deformation-density maps calculated were similar to those given by the X-ray diffraction method. The theoretical result suggested that the positive peaks on the threefold axes and the negative peaks on the metal—Cl bond axis correspond to the excess d electrons (4d of Pd and 5d of Pt) in the t 2g (dxy, dxz, dyz ) orbitals and the electron deficiency in the eg (dz 2,dx 2− y 2) orbitals, respectively. The positive and negative peak heights were calculated to be +1.8 and −0.8 e Å−3 for [PdCl6]2− and +1.2 and −0.6 e Å−3 for [PtCl6]2−. The effective charges and effective radii of Pd and Pt, and the number of electrons in the t 2g , eg and t 1u orbitals, were calculated by direct integration. The effects of the Madelung potential and electron correlation on the charge distributions of [PdCl6]2− and [PtCl6]2− were also analyzed.

Introduction to Relativistic Quantum Chemistry

2007 ◽  
Author(s):  
Kenneth G. Dyall ◽  
Knut Faegri
Keyword(s):  
Dirac Equation ◽  
Quantum Chemistry ◽  
Relativistic Theory ◽  
Density Functional ◽  
Relativistic Quantum ◽  
Relativistic Effects ◽  
Basis Sets ◽  
Spin Orbit ◽  
Approximate Methods ◽  
Nonrelativistic Theory

This book provides an introduction to the essentials of relativistic effects in quantum chemistry, and a reference work that collects all the major developments in this field. It is designed for the graduate student and the computational chemist with a good background in nonrelativistic theory. In addition to explaining the necessary theory in detail, at a level that the non-expert and the student should readily be able to follow, the book discusses the implementation of the theory and practicalities of its use in calculations. After a brief introduction to classical relativity and electromagnetism, the Dirac equation is presented, and its symmetry, atomic solutions, and interpretation are explored. Four-component molecular methods are then developed: self-consistent field theory and the use of basis sets, double-group and time-reversal symmetry, correlation methods, molecular properties, and an overview of relativistic density functional theory. The emphases in this section are on the basics of relativistic theory and how relativistic theory differs from nonrelativistic theory. Approximate methods are treated next, starting with spin separation in the Dirac equation, and proceeding to the Foldy-Wouthuysen, Douglas-Kroll, and related transformations, Breit-Pauli and direct perturbation theory, regular approximations, matrix approximations, and pseudopotential and model potential methods. For each of these approximations, one-electron operators and many-electron methods are developed, spin-free and spin-orbit operators are presented, and the calculation of electric and magnetic properties is discussed. The treatment of spin-orbit effects with correlation rounds off the presentation of approximate methods. The book concludes with a discussion of the qualitative changes in the picture of structure and bonding that arise from the inclusion of relativity.

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