Description

The conformer I of glycine is the one lowest in energy. It has an intermolecular H bond between the H atoms of the amino group and the O atom of the carboxyl group. The microwave frequencies have been reported by
(1) F. J. Lovas, Y. Kawashima, J.-U. Grabow, R. D. Suenram, G. T. Fraser, and E. Hirota, 1995, Astrophys. J. 455, L201.
The millimeter wave frequencies have been reported by
(2) V. V. Ilyushin, E. A. Alekseev, S. F. Dyubko, R. A. Motiyenko, and F. J. Lovas, 2005, J. Mol. Spectrosc. 231, 15.
Predictions of transitions with ΔKa>0 should be viewed with some caution because only a fairly small number of b-type transitions have been observed. Extrapolations are assumed to be reliable as long as the predicted uncertainties do not exceed 1MHz.
The 14N hyperfine splitting was resolved in (1). It may be resolved in cold sources or at lower frequencies. Therefore, separate predictions with hyperfine splitting are provided for J up to 10. The partition function takes into account the spin multiplicity gI = 3 of the 14N nucleus!
Glycine I has several low-lying vibrational modes; the lowest one is at about 72cm–1 or 104K. No vibrational state was considered in the calculation of the partition function!
The dipole moment was reported in (1).