Change with the Intermolecular Distance of Electron Properties of Hydrogen Bond Dimers at Equilibrium and Non-equilibrium Geometries

摘要

The change with the intermolecular distance R of a number of electron properties obtained from the electron density ρ(r) and the electron localization function η(r) along with some selected structural features is investigated for seven dimers linked by conventional hydrogen bonds (HBs). Five non-equilibrium geometries apart from the equilibrium one are optimized in MP2/6-311++G(d,p) ab initio calculations for every dimer. The variation with R of topological descriptors and integrated properties computed from ρ(r) and η (r) reveals that not only features characteristics of hydrogen bonding are still noticed inside the equilibrium distance R eq but the sign and magnitude of HB trends are kept at R < R eq. Only at the shortest intermolecular distances where dramatic structural changes occur, these trends revert their direction although in most cases HB characteristics are still noticed.