Nature of the Frequency Shift of Hydrogen Valence Vibrations in Water Molecules

Abstract

The physical nature of a frequency shift of hydrogen valence vibrations in a water molecule due to its interaction with neighbor molecules has been studied. Electrostatic forces connected with the multipole moments of molecules are supposed to give a dominating contribution to the intermolecular interaction. The frequency shift was calculated in the case where two neighbor molecules form a dimer. The obtained result is in qualitative agreement with the frequency shifts observed for water vapor, hexagonal ice, and liquid water, as well as for aqueous solutions of alcohols. This fact testifies to the electrostatic nature of H-bonds used to describe both the specific features of the intermolecular interaction in water and the macroscopic properties of the latter. K e y w o r d s: frequency shift, hydrogen valence vibrations, electrostatic models of water molecule, dimer.

Physical Nature of Hydrogen Bond

“…One may get convinced (see work [25]) that, by the order of magnitude in the framework of the electrostatic model, the ratio ∆r H1 /r H1 , where ∆r H1 = = r′ H1 − rH1 , satisfies the inequality ∆r H1 /r H1 ∼ (r H1 /r O1O2 ) 4 ≤ 0.02.…”

“…Our conclusions are based on the results obtained for the temperature dependences of the self-diffusion and kinematic shear viscosity coefficients, specific volume, evaporation heat [22], and heat capacity of water [17,23,24]. In addition, we analyze the frequency shift for valence hydrogens in the water molecule [25] and the variation of its dipole moment under the action of environmental molecules [3].…”