The microwave spectrum of acetaldehyde cyanohydrin

The microwave spectrum of acetaldehyde cyanohydrin shows two series of μ_aR branch transitions of almost equal intensity which are accompanied by similar patterns of vibrational satellites. The most probable explanation of these two series of lines consistent with the expected conformational behaviour of acetaldehyde cyanohydrin is that they belong to the two non-equivalent rotamers in which the hydroxyl group is gauche to the cyanide group.