ABINITIO STUDY OF THE CONFORMATIONAL EQUILIBRIUM OF ETHYLENE-GLYCOL

The conformational equilibrium of ethylene glycol (CH2OHCH2OH) has been examined by performing geometry optimizations at the 6-31G*, MP2/6-31G* and 6-31G** levels. Final energies have been calculated at the MP3 level with the optimized geometries. The two most stable conformers are a tGg' and gGg' but it is verified that the inclusion of electronic correlations reduces their energy difference of 0.6 kcal/mol at the HF level to less than 0.2 kcal/mol. The possible coexistence of the two most stable conformers is in agreement with some previous studies of Frei et al. For the tXg' conformer a detailed analysis of the intramolecular potential as a function of rotation around the C-C bond is also reported.