Fock space multireference coupled cluster calculations based on an underlying bivariational self-consistent field on Auger and shape resonances

2004 ◽  
Vol 120 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Y. Sajeev ◽  
Manoj K. Mishra ◽  
Nayana Vaval ◽  
Sourav Pal
Keyword(s):  
Fock Space ◽  
Coupled Cluster ◽  
Consistent Field ◽  
Cluster Calculations ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Coupled Cluster Calculations ◽  
Shape Resonances

On the dissociation energy of Ti(OH2)+. An MCSCF, CCSD(T), and DFT study

1996 ◽  
Vol 74 (10) ◽  
pp. 1824-1829 ◽  
Author(s):  
A. Irigoras ◽  
J.M. Ugalde ◽  
X. Lopez ◽  
C. Sarasola
Keyword(s):  
Dissociation Energy ◽  
Density Functional ◽  
Basis Sets ◽  
Coupled Cluster ◽  
Functional Theory ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Self Consistent Field Theory ◽  
Effective Core Potentials

The dissociation energy of the Ti(OH2)+ ion–molecule complex was calculated by the multiconfigurational self-consistent field theory, coupled cluster theory, and two density functional theory based methods, using both all-electron basis sets and effective core potentials. The calculations show that approximate density functional theory gives results in better agreement with experiment than either the multiconfigurational self-consistent field theory or the coupled cluster theory, with both all-electron basis sets and effective core potentials. Nevertheless, the optimized geometries and harmonic vibration frequencies are very similar, irrespective of the level of theory used. The interconfigurational energy ordering of the two valence electronic configurations dn−1s and dn−2s2 of the 4F electronic state of the titanium cation were also calculated and are discussed. Key words: ab initio, dissociation energy, ion–molecule complex, effective core potentials, transition metals.

On the performance of two-component energy-consistent pseudopotentials in atomic Fock-space coupled cluster calculations

2008 ◽  
Vol 128 (2) ◽  
pp. 024106 ◽  
Author(s):  
Detlev Figgen ◽  
Anja Wedig ◽  
Hermann Stoll ◽  
Michael Dolg ◽  
Ephraim Eliav ◽  
...  
Keyword(s):  
Fock Space ◽  
Coupled Cluster ◽  
Cluster Calculations ◽  
Two Component ◽  
Coupled Cluster Calculations

I. First Principles Cluster Calculations for the Electronic Structures of CuO7 Octahedron and CuO5 Pyramid

1997 ◽  
Vol 11 (32) ◽  
pp. 3733-3750 ◽  
Author(s):  
Akihiro Sano ◽  
Mikio Eto ◽  
Hiroshi Kamimura
Keyword(s):  
First Principles ◽  
Electronic Structures ◽  
Field Method ◽  
Strongly Correlated ◽  
Cluster Systems ◽  
Consistent Field ◽  
Cluster Calculations ◽  
Self Consistent ◽  
Self Consistent Field

In this paper we first describe the multi-configuration self-consistent field method with configuration interaction (MCSCF-CI) which is a variational method most suitable for strongly-correlated cluster systems. Then the calculated results of CuO 6 cluster embedded in hole-doped La 2-x Sr x CuO 4 and of CuO 4 cluster in the electron-doped Nd 2-x Ce x CuO 4 are reviewed. Finally the calculated results on the electronic structure of CuO 5 pyramid embedded in the insulating YBa 2 Cu 3 O 6 and superconducting YBa2Cu3O7 are newly presented. In the latter case we will clarify an important role of the Cu-O chain in the electronic and superconducting state of YBa2Cu3O7 .

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