Physical nature of interactions in charge-inverted hydrogen bonds

Based on the hybrid variational-perturbation decomposition scheme we show that the electrostatic and delocalization energy terms are the most stabilizing components of the interaction energy of the charge-inverted hydrogen-bond (CIHB). It is shown that the electrostatic multipole term is the only one that closely reproduces the MP2 minimum conformation thus indicating that the bent structure results from a peculiar distribution of charge that can be described by atomic multipole moments of interacting monomers. To isolate the origin of observed bending of CIHB idealized linear structures have been analyzed as well. In this case the delocalization energy term outweighs all other stabilizing terms.