A new measure of hydrogen bonding strength – ab initio and atoms in molecules studies

MP2/6-311++G∗∗ calculations were performed on HF⋯H2O, HF⋯NH3, HF⋯LiH, (H2O)2, (HCOOH)2,C2H2⋯H2O, H2O⋯NH3, (C2H2)2 complexes to characterise different hydrogen bonds; typical as O–H⋯O and O–H⋯N, weak like C–H⋯O and C–H⋯π, dihydrogen bonds, etc. For such heterogeneous samples a new measure of hydrogen bond strength was introduced. The Bader theory was also applied to characterise hydrogen bonds.