IR–Microwave Double Resonance Studies of Tunneling Frequencies in the ν1and ν3States of Ammonia

Abstract

Infrared laser-microwave double resonance spectroscopy has been used to observe tunneling transitions in the ν1and ν3hydrogen stretching states of NH3. Inversion frequencies in 15 rotational states of ν1and 6 rotational states of ν3were measured to accuracies of ±25 kHz. Comparisons between ground state andv1= 1 data indicate thatx–yCoriolis interactions are responsible for much of the angular momentum dependence of the ν1inversion splittings. TheJ,Krotational quantum number dependence for tunneling in ν3is very different from that in either the ground state or ν1.