CHARACTERISTICS AND SOME PECULIARITIES OF MULTICONFIGURATIONAL SELF-CONSISTENT FIELD STATIONARY-POINTS OF THE LI- GROUND-STATE

We examine in detail the multiconfigurational self-consistent field (MCSCF) energy hypersurface of the ground state of Li- using a previously reported Cartesian Gaussian basis set and several previously used different choices of complete active space (CAS). For many of the CASs we show there are many close-lying (in energy) stationary points that have the correct number of negative eigenvalues in the total Hessian with respect to real variations of the orbital and configurational parameters and correspond to the lowest energy eigenvector in the configuration interaction (CI) which uses the MCSCF orbitals and configurations. These stationary points may be obtained with any of the current, forefront MCSCF codes. More detailed examination of these stationary points shows that some of these are improper and that some do not correspond to the most "desired" stationary point. The presence of two nearby proper, desired MCSCF stationary points with the 2-3s, 2-3p CAS is troubling. 1990 American Institute of Physics.

CHARACTERISTICS AND SOME PECULIARITIES OF MULTICONFIGURATIONAL SELF-CONSISTENT FIELD STATIONARY-POINTS OF THE LI- GROUND-STATE Academic Article