The Infrared Spectrum of NH3/u - d nu/ Trapped in Solid Neon
Marilyn E. Jacox, Warren E. Thompson
The infrared spectra of normal and deuterium-enriched Ne:NH3u = 1600:1 deposits at 4.3 K have been observed, and structure associated with almost all of the vibrational fundamentals has been assigned. Although the most prominent absorptions arise from the ground-state J = 0 level(s), incomplete nuclear spin equilibration enhances the contribution of absorptions arising from the ground-state J = 1 levels. As had been proposed in an earlier study, the inversion splitting for the v2u fundamental is appreciably reduced from that observed for the gas-phase molecule, but the rotational structure associated with the J = 1 levels of the vibrationally excited molecule is only slightly perturbed. Ammonia is trapped in two different types of site in solid neon. Matrix shifts from the corresponding gas-phase absorptions amount to only a few cm1d, and are smaller than those previously reported for ammonia trapped in an argon matrix.