Yuthana TantirungrotechaiMahidol University2018-07-242018-07-242003-04-25Journal of Molecular Structure: THEOCHEM. Vol.624, No.1-3 (2003), 279-286016612802-s2.0-0037466299https://repository.li.mahidol.ac.th/handle/20.500.14594/20739Torsional potential of glyoxal was studied under the presence of an external electric field at the MP2/TZ2P + f level. Without an external electric field, the trans conformer is more stable than the cis conformer by 4.51 kcal/mol. The cis conformer which points two hydrogens in the field direction is stabilized when a large electric field is applied along the C2 symmetry axis, whereas the stationary point at the trans conformer disappears. The effect of a neighbouring atom was investigated by considering the complex of glyoxal with Ar and Na+. The Ar···glyoxal complex is very weakly bound. Several stationary points on the potential energy surface were located. All stationary structures corresponding to the Ar···trans-glyoxal have lower energy than those of the Ar···cis-glyoxal. The Na+···glyoxal complex has two minimum structures; the glyoxal molecule in the most stabilized complex has the cis conformation. This indicates that the interaction of glyoxal with Na+ is sufficient to change the glyoxal conformation. © 2003 Published by Elsevier Science B.V.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyChemistryPhysics and AstronomyArticleSCOPUS10.1016/S0166-1280(02)00792-3