Organic compounds in the C_(3)H_(6)O_(3) family: Microwave spectrum of cis–cis dimethyl carbonate

Geometry optimization calculations on 13 members of the C_(3)H_(6)O_(3) family of organic species have been carried out to determine their relative binding energies. Dimethyl carbonate [(CH_3)_(2)CO_3] is one of the lower energy species in this family, which includes the C_3-sugars 1,3-dihydroxyacetone and glyceraldehyde. The microwave spectrum of dimethyl carbonate has been measured over the frequency range 8.4–25.3 GHz with several pulsed-beam Fourier-transform microwave spectrometers and from 227 GHz to 350 GHz with direct absorption spectrometers. The spectrum of the lowest-energy cis–cis conformer of dimethyl carbonate has been assigned, and ab initio electronic structure calculations of the three possible conformers have been performed. Stark effect measurements were carried out on the cis–cis conformer to provide accurate determinations of the dipole moment components.