Ab initio GB study of conformational space of d-glyceraldehyde in aqueous solution

Abstract

Conformation of d-glyceraldehyde in aqueous solution was analyzed by the ab initio GB method which includes the solvent effect as a continuum model using the generalized Born formula. The energy hypersurface defined by four torsion angles was represented by the HFGB/3-21G energies for the conformation generated by changing each torsion angle in steps of 30°. The 27 local minima were found by the steepest descent searching on the energy surface, and the barrier height between two minima was estimated by the analysis of the ridge separating the two minima. These data were represented as a conformational space map (COSMAP) which gives a qualitative picture of the conformational energy hypersurface of d-glyceraldehyde. Starting from each local minimum in the COSMAP, the structure of d-glyceraldehyde in aqueous solution was fully optimized for 10 low-energy conformations using the 6-31G∗∗ basis set.