Natural bond orbital analysis of near‐Hartree–Fock water dimer

摘要: We have carried out a natural bond orbital analysis of hydrogen bonding in the water dimer for near‐Hartree–Fock wave function Popkie, Kistenmacher, and Clementi, extending previous studies based on smaller basis sets less realistic geometry. find that interactions which may properly be described as ‘‘charge transfer’’ (particularly n‐σ*OH interaction along H‐bond axis) play critical role formation bond, without these would 3–5 kcal/mol repulsive at observed equilibrium distance. discuss this result relationship to Klemperer’s general picture van der Waals molecules, theoretical analyses by method Kitaura Morokuma.