MICROWAVE AND SUBMILLIMETER SPECTROSCOPY OF AR-NH3 STATES CORRELATING WITH AR+NH3 (J=1,KAPPA=1)

Microwave and submillimeter transitions for Ar-NH3 have been observed and assigned for the SIGMA and PI-states correlating asymptotically with Ar + NH3 (j = 1,\k\= 1). The SIGMA-states are found to lie below the PI-states and are separated by approximately the inversion splitting of free NH3. For the PI-states the NH3 inversion tunneling is nearly quenched, being only weakly allowed through Coriolis interactions with the nearby-SIGMA-states. The observed microwave and submillimeter spectra also allow the determination of N-14 quadrupole coupling constants and relative submillimeter absorption intensities. All the above results are interpreted using a model internal-rotation inversion Hamiltonian, leading to detailed information about the anisotropy of the intermolecular potential.