Inversion splittings of SiH3-. An ab initio study

Accurate higher-order coupled cluster (CC) and conventional multi-reference configuration interaction (MR-CI) approaches are used to construct the inv ersion potential energy function of the silyl anion (SiH3-). From these pot ential functions, the splittings of the lower inversion vibrational levels are estimated using the nonrigid inverter theory. The MR-CI results compare well with the results obtained from different levels of coupled cluster th eory (CCSD and CCSD(T)), and it is found that the predicted inversion split tings exhibit only a moderate dependence on the different approximation lev els of ab initio theory. The magnitudes of the calculated splittings, indic ate that for states with V-2 greater than or equal to 4 they could possibly become observable using currently available experimental techniques. (C) 2 001 Elsevier Science B.V. All lights reserved.