Molecular one-electron properties using the multireference Hartree-Fock CI method

The recently introduced multireference Hartree-Fock configuration interaction (MRHFCI) method has been applied to the calculation of the dipole moment of the LiH, BH, FH, CO, and H2O molecules. The results obtained indicate that MRHFCI wave functions, Much more compact but of the same quality of the orthogonal full CI ones, can provide better dipole moments than the corresponding full CI wave functions. The value of the dipole moments obtained with the MRHFCI wave functions is quite insensitive to the choice of the HF references but the same is not true for the eletronic energy. Therefore, further Studies are necessary to develop a criterion for selecting a set of HF references which could provide the best values of energy and dipole moment. Also, it Would be important to verify if other one-electron properties can be computed with the same degree of accuracy obtained for the dipole moments. (C) 2008 Wiley Periodicals, Inc.