Relativistic DV-Xa method

In the present work we first perform molecular orbital (MO) calculations using the relativistic DV-Xa method. Then we perform Cl calculations using the DVME method to obtain the energy levels and wave functions of a many-electron system, which will be used for calculations and analysis of the optical spectra of RE ions in crystals. 

Invited 17. Hisashi Yoshida and Kazuyoshi Ogasawara (NEC Lighting, Ltd., Kwansei Gakuin University) A Novel Study of Phosphors using Relativistic DV-Xa Method... 

The authors thank Prof. K. Oagasawara and Mr. H. Yoshida for the development of the relativistic DV-Xa method code (RSCAT) and offering it to us. 

When our present group became interested in quasi-molecules, which are generated in atomic collision systems, we started to use the relativistic DV Xa-method. With the help of Arne Rosen we were the first to calculate correlation diagrams of relatively heavy systems. ... 

Since the relativistic DV-Xa method takes into account fully relativistic effects under Slater s exchange potential approximation, this is very useful for studying the electronic structures and chemical bonding in molecules containing heavy... 

We evaluated adsorbed SO3 configuration on Pt (111) surface by using the first-principles calculations with a slab model in a periodic boundary condition. On the basis of the result of the calculations with a slab model, we evaluated the electronic states of SO3 in detail using the relativistic DV-Xa molecular orbital method. 

In the relativistic DVME method, first, the relativistic DV-Xa calculation [22] is performed to obtain the fully relativistic four-component MOs used for the Cl calculations. 

In the DVME method, the many-electron Hamiltonian is diagonalized based on the Cl approach. In this approach, the Zth many-electron wave function Fi is represented as a linear combination of the Slater determinants which are constructed from MOs obtained by the relativistic DV-Xa calculations as ... 

To elucidate the nature of chemical bonding in metal carbides with the NaCl structure, the valence electronic states for TiC and UC have been calculated using the discrete-variational (DV) Xa method. Since relativistic effects on chemical bonding of compounds containing uranium atom become significant, the relativistic Hamiltonian, i.e., the DV-Dirac-Slater method, was used for UC. The results... 

We used the DV Hartree-Fock-Slater method for TiC, while for UC we used the DV Dirac-Slater (DV-DS) method taking fully relativistic effects into account. The basis functions used were ls-2p for C atom, ls-4p for Ti atom, and ls-7p for U atom. The bond nature of TiC and UC compounds were studied by Mulliken population analysis [6,7]. The details of the nonrelativistic and relativistic DV-Xa molecular orbital methods have been described elsewhere [7,8,9]. 

DV-Xa methods. It was found that relativistic effects become significant in chemical bonding of molecules containing heavy elements with Z larger than 50 and APb of the XFg (X=S to W) shows a Z -dependence similar to that of ARg for the hydrides [1]. On the other hand, the atomic-number dependence of APb for actinide compounds such as UFg was not well explained using the Z -dependence. However, the number of examples examined in the previous work are not satisfactory for discussing the reason for the dependence of APb-... 

The relativistic DV-Xa calculations are based on the one-electron Hamiltonian for the Dirac-Slater MO method which is given as... 

The electronic state calculations of transition metal clusters have been carried out to study the basic electronic properties of these elements by the use of DV-Xa molecular orbital method. It is found that the covalent bonding between neighboring atoms, namely the short range chemical interaction is very important to determine the valence band structure of transition element. The spin polarization in the transition metal cluster has been investigated and the mechanism of the magnetic interaction between the atomic spins has been interpreted by means of the spin polarized molecular orbital description. For heavy elements like 5d transition metals, the relativistic effects are found to be very important even in the valence electronic state. 

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