Acetamide planarity revisited: Density functional and second order Moeller-Plesset perturbation studies

摘要

Density functional theory (DFT) with nonlocal functionals, BLYP, BP86,B3LYP and ACM, with split-valence basis sets has been applied to the prediction of molecular structure and torsional barrier of acetamide, a peptide mimic. Moeller-Plesset calculations truncated to the second order (MP2) have been performed on acetamide for comparison with DFT results. The conformation of the methyl group observed in MP2 calculations is different from that in DFT calculations. DFT promises to be a powerful method for molecular structure determination and conformational analysis of peptides in future at the same level of accuracy as NMR, X-ray crystallography and neutron diffraction.