Ab Initio MRCI Calculation and Modeling of the A1Pi Potential Energy Curve of CO

We report a MRCI study of the A1Pi potential energy curve of CO. The calculated ab initio energies are analytically modeled using the EHFACE2 and RKHS methods. A barrier of approximately 730 cm-1 is predicted at an internuclear distance of approximately 4.2a0 in agreement with previous calculations and spectroscopic measurements. The origin of such a barrier is briefly discussed. Copyright 1998 Academic Press.