A new approach for establishing the G-particle-hole Hyperivirial (GHV) equation for singlet excited states

C. VALDEMORO; L.M. TEL; D.R. ALCOBA; E. PEREZ-ROMERO

Cambridge

Workshop; 15th European Workshop on Quantum Systems in Chemistry and Physics; 2010

University of Cambridge

The GHV method has been very sucessful in the study of those states whose zero-order wave-function is resonably described by a single Slater determinant, but it failed in the study of multi-referenced highly correlated states. The main cause for this limitation of the GHV method is that the approximating algorithms for the 3-body Correlation matrix elements are not adequate when the density occupation number of the natural-orbitals differs substantially from 1 or from zero. This problem is tackled here for Singlet states where the size of the equation as well as the number of the 3-body Correlation matrix unknowns can be considerably reduced. A preliminar set of approximating algorithms for these 3-body unknowns is reported.