Conformation and parity-violating energy of hydrated d-glyceraldehyde in aqueous solution

Abstract

Conformation of hydrated d-glyceraldehyde ( d-glyceraldehyde hydrate, d-GAH) in aqueous solution was analyzed by ab initio generalized Born (GB) method including the solvent effect by the continuum model using the generalized Born formula. The energy surface defined by six torsion angles of d-GAH was represented by the HF-GB/STO-3G energies for the conformations generated by changing each torsion angle in steps of 30 or 60° and the 164 local minima were found in this energy surface. The 10 low-energy structures of d-GAH in aqueous solution were obtained with the 6-31G ∗∗ basis set. In these structures, intramolecular hydrogen bondings were recognized. The parity-violating energy, E pv, was calculated by using the spin-orbit-coupling (SOC)-SCF/5s2p wavefunction. The calculated E pv values of the 164 conformations indicated that the E pv value of d-GAH depends largely on the conformation; half of the conformations have positive E pv and the other half have negative E pv. The lowest energy conformation determined by the 6-31G ∗∗ calculation has a negative E pvvalue of −1.63×10 −20 hartree and the energy-averaged E pv value is −1.12×10 −20 hartree, suggesting that hydrated d-glyceraldehyde is more stable than hydrated l-glyceraldehyde in aqueous solution due to the parity-violating weak neutral current interaction.