Correlated level ab initio calculations (large basis set MP2, and MP4, CCSD, and CCSD(T) computations) have been performed for 13 conformers of neutral glycine, including all 8 possible conformers with planar heavy-atom arrangements. These calculations resulted in accurate geometric structures, relative energies, harmonic vibrational frequencies, and infrared intensities for all conformers. The structural results obtained support the rotational constants measured for the two lowest-energy forms of glycine, and their high accuracy should be profitable in the search for other conformers by rotational spectroscopy. Energetic, structural, and quadratic force field results indicate possible model improvements for an existing gas-phase electron-diffraction study of the lowest-energy conformer. Predictions, probably accurate to within about 100 cm−1, are made for the order and relative energy of all conformers considered.
ASJC Scopus subject areas
- Colloid and Surface Chemistry