The change in the vibrational anharmonicity for FH⋯Rg, FArH⋯Rg, FArH⋯N2 and FArH⋯P2 (Rg=Ne, Ar, Kr)

The change in the vibrational anharmonic constant for the linear hydrogen-bonded complexes FH⋯Rg, FArH⋯Rg, FArH⋯N2, FArH⋯P2 (Rg=Ne, Ar, Kr) was determined at the MP2/6-311++G(3df,3pd) level of theory. It was found that in the vibrationally red-shifted complexes, hydrogen bond formation increases the anharmonic constant while in the vibrationally blue-shifted species (except FArH⋯Ne) the anharmonic constant decreases on complexation.