Molecules containing very heavy atoms

There are several review articles (Pitzer 1979, Pyykko and Desclaux 1979, Krauss and Stevens 1984, Balasubramanian and Pitzer 1987, Malli 1982a, b, Christiansen etal. 1985, Pyykko 1986, 1988, Balasubramanian 1989a, b, 1990a, b) which deal with the importance of relativistic effects on the chemical and spectroscopic properties of molecules containing very heavy atoms. For a detailed description of these effects and a survey of the literature, the reader is referred to these reviews. However, in this chapter... 

Another relativistic effect of considerable importance in the chemical properties of molecules containing very heavy atoms is the spin orbit interaction. The spin-orbit interaction is a relativistic effect in the sense that it goes to zero in the limit c -> oo due to the presence of (a = 1/c) term in the numerator of the spin-orbit operator. Physically it arises from the coupling of the orbital angular momentum (/) of the electron with its spin (s). As Z (the atomic number) increases, the coupling of / and s increases significantly. Thus a new quantum number for the atoms, j = l + s, becomes a good... 

Desclaux s (1975) numerical Dirac-Fock implementation in a computer is widely used to generate relativistic numerical all-electron wavefu notions for almost any atom in the periodic table. This appears to be one starting point for ab initio relativistic quantum computations of molecules containing very heavy atoms. 

See Density Functional Theory (DFT), Hartree-Fock (HF), and the Self-consistent Field Relativistic Effective Core Potential Techniques for Molecules Containing Very Heavy Atoms Transition Metal Chemistry and Transition Metals Applications. 

Density Functional Applications Density Functional Theory (DFT), Hartree-Fock (HF), and the Self-consistent Field Density Functional Theory Applications to Transition Metal Problems ESR Hypeifine Calculations Gradient Theory Metal Complexes Molecular Magnetic Properties NMR Chemical Shift Computation Ab Initio NMR Chemical Shift Confutation Structural Applications NMR Data Correlation with Chemical Structure Relativistic Effective Core Potential Techniques for Molecules Containing Very Heavy Atoms Relativistic Effects of the Superheavy Elements Relativistic Theory and Applications Transition Metal Chemistry Transition Metals Applications. 

Relativistic Effective Core Potential Techniques for Molecules Containing Very Heavy Atoms... 

Ever since the 1970s relativistic quantum computations of atoms and molecules containing very heavy atoms and the related developments of techniques have been the topic... 

COMPUTATIONAL TECHNIQUES FOR MOLECULES CONTAINING VERY HEAVY ATOMS... 

Ab initio methods for molecules containing very heavy atoms are based on the effective core potential (ECP) method, especially if the molecules in question, have several heavy atoms. The philosophy of the ECP method is to replace the chemically unimportant core electrons by an effective core potential, and treat the remaining valence electrons explicitly. There are several techniques to derive RECPs, as seen from... 

While these computational techniques include electron correlation effects, they exclude spin-orbit coupling, which is quite significant for molecules containing very heavy atoms. Christiansen et al. have developed the relativistic Cl(RCl) method to introduce electron correlation and spin-orbit coupling simultaneously for diatomics based on a SCF procedure. In the RCf method, all electronic configurations, which can... 

The final consequence of such a strategy would be to try to eliminate the degrees of freedom of the core electrons as well and to introduce a possibly nonlocal effective potential (pseudopotential), the parameters of which are adjusted either to experiments, which are relativistic from the very beginning, or suitable atomic properties derived from relativistic calculations. This method has developed to the real working horse of relativistic quantum chemistry, and several variants are known as relativistic pseudopotentials, effective core potentials (ECPs) or ab initio model potentials. See Relativistic Effective Core Potential Techniques for Molecules Containing Very Heavy Atoms. 

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