Vibrational analysis of water clusters by quantum chemical methods

Calculation of gas and liquid phase spectra of the water dimer, trimer, tetramer and pentamer

Abstract

Vibrational frequencies and infrared intensities of water dimer, trimer, tetramer and pentamer have been calculated with ab initio and density functional methods. Onsager model was also utilized to obtain the frequencies and infrared intensities in the liquid water as the solvent. Calculated spectra were compared with the FT-IR spectrum of liquid water. The presence or absence of water clusters in the liquid water has been discussed. The calculated stretching frequencies of the cyclic tetramer and pentamer indicated that these species are by no means the main structure of the liquid water at least qualitatively.