15min:

M. D. ALLEN, K. M. EVENSON, Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80303-3328; AND J. M. BROWN, The Physical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, United Kingdom.

Vibration-rotation transitions between the (010) µ^2- - (000) X²_r vibronic states, were recorded using far-infrared laser magnetic resonance (FIR-LMR) spectroscopic techniques. These transitions occur near 200 cm^-1 for the (010) µ^2- - (000) X²_1/2 transition and 160 cm^-1 for the (010) µ^2- - (000) X² _3/2 transition. This is the first direct measurement of the ₂ band of CCN and in conjunction with a fit of optical data, similar to the one found in the paper by Kohguchi et al., has resulted in an accurate determination of the bending vibration frequency and the Renner parameter. The data were fit using an N² effective Hamiltonian modified to include the Renner-Teller effect.