MOLECULAR EXCHANGE-CORRELATION KOHN-SHAM POTENTIAL AND ENERGY DENSITYFROM AB-INITIO FIRST-ORDER AND 2ND-ORDER DENSITY-MATRICES - EXAMPLES FOR XH (X=LI, B, F)

The molecular Kohn-Sham exchange-correlation potential upsilon(xc) and the energy density epsilon(xc) have been constructed from ab initio f irst- and second-order density matrices for the series XH (X=Li, B, F) . The way various effects of electronic structure and electron correla tion manifest themselves in the shape of upsilon(xc) and epsilon(xc) h as been analyzed by their decomposition into various components; the p otential of the exchange-correlation hole, the kinetic component and ( in the case of upsilon(xc)) the ''response'' component. The kinetic en ergy of noninteracting particles T-s, the kinetic part of the exchange -correlation energy T-c, and the energy of the highest occupied molecu lar orbital epsilon(N) have been obtained with reasonable accuracy and the effect of bond formation on these functionals has been studied.(1 ) (C) 1996 American Institute of Physics.