H / D isotope effect on the dihydrogen bond by ab initio path integral molecular dynamics simulation

Abstract

We have performed ab initio path integral molecular dynamics (PIMD) simulation for the isotopomers of C2H2…HLi cluster to discuss the thermal, quantum, and isotope effects on the average geometries, which are compared with classical MD and equilibrium geometries. The π…lithium bonding with T-shape geometry is more stable than the dihydrogen bonded linear geometry by both PIMD, classical MD, and equilibrium geometry. Our ab initio PIMD simulation has clearly demonstrated the H/D isotope effect on intermolecular fluctuation, that is, the out-of-plane and in-plane fluctuations are characterized for LiH and LiD moieties, respectively.