The lengthening of the H-X bond in B · H-X van der waals complexes

Abstract

A simple relation is presented between the bond lengthening, δ r, and the vibrational frequency decrease for the Morse oscillator H-X coupled by the van der Waals bond to a structureless moiety B. Estimates of δ r(HX) in the series of complexes B · HX (X = F,Cl) range from 0.0002 Å for Ar · HCl to 0.04 Å for Me 2O · HF. For the B · HF dimers, the predicted values of δ r(HF) are in excellent agreement with the theoretical results reported by Liu and Dykstra.