An interpretation of the evolution with temperature of the ν2+ν3 combination band in water

Abstract

The near infrared absorption spectra of water around 5000 cm⁻¹ have been obtained at different temperatures, in the range of −50°C to 50°C. The complex band has been resolved into three component bands centered at 5200, 5080 and 4920 cm⁻¹, and having half‐widths of 140, 200, and 340 cm⁻¹, respectively. These bands have been associated with the existence of three species of water molecules with hydrogen bond energies distributed around three maxima. From the study of the evolution of the intensities of these component bands with temperature we have determined the energy ΔH° involved in the transition of molecules from one to another of the three energy states, both in liquid water and ice. Any of these values can be taken as a thermodynamic parameter characteristic of water and its variation constitutes a criterium for ascertaining changes in the physical state of water, e.g., changes induced by the proximity of solid surfaces.