Jahn-Teller and related effects in the silver trimer. I. The ab initio calculation of spectroscopically observable parameters for the X̃E′2 and ÃE″2 electronic states

Extensive ab initio calculations were performed for the XE′2 and AE″2 states of Ag3, using a newly constructed basis set for Ag. An important goal of these calculations is to guide the analysis of the experimentally observed AE″2-XE′2 electronic spectrum. Vibrational frequencies of Ag3 for both the X and A states are reported. Spectroscopically obtainable parameters describing the Jahn-Teller effect are calculated for the X and A states. The magnitude of the spin-orbit effects for this relativistic system was also calculated for the XE′2 and AE″2 states. Using all this information, the X-A electronic spectrum is predicted for Ag3. Additionally, the geometries and symmetries of the global minima and saddle points as well as the barrier to pseudorotation around the moat of the potential energy surface are determined for both states.