Calculation of the potential energy surface for intermolecular amide hydrogen bonds using semiempirical and ab initio methods

The dependence of hydrogen-bond strength on the hydrogen bonding distance and hydrogen bond angles of intermolecular hydrogen bonds were analyzed by utilizing ab initio computational methods. The hydrogen bonding distance of the amide hydrogen bonds were 2.1 amstrong with minimum steric overlap due to low interactions between the two formamides. The hydrogen bond between two N-methylacetamide exhibits decreasing constant interaction energy compared to the hydrogen bond of the intermollecular formamide.