Vaporization heat and vibrational frequency relation in diatomic liquids

Abstract

It is shown that a parabolic relation exists between the latent heat of evaporation and the internuclear vibration frequency in diatomic liquids at the normal boiling point. The proposed relation is: Y=2·485 − 0·013X − 0·02X 2 where X = ln ( hc ω e / kT b ); Y = ln ( ΔH ν / RT B ); and ω e is the vibrational frequency in cm −1; while ΔH ν is the latent heat of vaporization at the normal boiling point temperature T B . The possibility of interpreting the evaporation process on the basis of thermally excited vibrational state of molecule in terms of intermolecular force field interaction in liquid state, is subsequently shortly indicated.