Pauli terms

Table 9 shows that the latter prediction is supported by the EDA results as far as the contributions of the orbitals with different symmetry to the AEo term is concerned. 90.4% of the latter come from the ti orbitals. The d orbitals of Xe do not play a role for the Xe F bonds. The contributions of the eg and t2g orbital interactions are neghgible. However, the EDA results show also that the attractive orbital interactions are compensated by the repulsive Pauli term. Xenon hexafluoride is stable because there is strong quasi-classical Coulomb attraction between Xe and Fe. The sum of the quantum theoretical expressions (AEorb and AEpauu) is destabilizing. 

The individual terms that sum up to AEint show, that the largest contribution to the interatomic interactions in N2 comes from the Pauli repulsion AEpauu. The absolute value of the attractive orbital term = —715.4 kcal/mol is smaller than the Pauli term AEpauii = 791.7 kcal/mol by 76.3 kcal/mol. This in turn means that the quasiclassical electrostatic attraction = —308.5 kcaFmol is larger than the BDE =... 

In metallic systems, the temperature-independent Pauli susceptibility is a characteristic feature for delocalised carriers [18]. The Pauli susceptibility is directly proportional to the density of states at the Fermi level, i.e. = fPgN(Ep). where p. is the Bohr magneton and N Ep) is the density of states at the Fermi level. Hence, it is possible to determine the N Ep) from the temperature-independent for metallic systems. Usually, in disordered systems, the measured is the sum of both Curie and Pauli terms the Curie term gives an estimate of the localised spins present in the system, and this in turn is a measure of the extent of disorder. 

The Curie term in x(T) is rather dominant at low temperatures for systems in the critical and insulating regimes, and the temperature independent Pauli term is usually observed at temperatures greater than 100 K. However, xiT) Is not as sensitive as o(T) and MR for identifying the metallic, critical and insulating regimes near the M-I transition [17]. 

The Pauli Hamiltonian is ideally suited for carrying out relativistic corrections as a first-order perturbation to a non-relativistic Hamiltonian. In recent years, several authors have considered inclusion of the Pauli terms in variational self-consistent field (SCF) calculations. Wadt, Hay and... 

Relativistic corrections have also been included in DFT calculations using perturbation theory, first by Herman and Skillman (1963) and later by Snijders and Baerends (Snijders 1979, Snijders and Baerends 1977, 1978). Following a non-relativistic Hartree-Fock-Slater calculation, first-order perturbation theory was used to calculate the relativistic corrections from the Breit-Pauli terms of 0(c ). Herman and Skillman applied this approach to first order only for the energies. 

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