The conformational landscape of 1,2-propanediol was investigated by quantum chemical calculations from
(1) F. J. Lovas, D. F. Plusquellic, B. H. Pate, J. L. Neill, M. T. Muckle, and A. J. Remijan, 2009, J. Mol. Spectrosc. 257, 82.
The aG'g conformer was found to be the lowest one with the gG'a conformer calculated to be 106 K higher in energy and the g'G'g conformer 165 K higher. The gG'g' conformer is the fifth one in energy, calculated to be 331 K above the lowest.
Several higher lying conformers of 1,2-propanediol were studied recently by
(2) O. Zakharenko, J.-B. Bossa, F. Lewen, S. Schlemmer, and H. S. P. Müller, 2017, J. Mol. Spectrosc. 333, 23.
This analysis also included data from (1). The present analysis includes for completeness reason data from
(3) B. E. Arenas, S. Gruet, A. L. Steber, and M. Schnell, 2017, J. Mol. Spectrosc. 337, in press.
As there are uncertainties concerning the exact energy differences among the conformers, we treat each conformer as isolated species.
According to (2), small perturbations occur at higher J (above 40), so predictions should be viewed with some caution. Nevertheless, the predictions are expected to be sufficient for all astronomical observations. Predictions with uncertainties larger than 0.3 MHz should also be viewed with caution.
The dipole moment components are from a quantum chemical calculation from (1).