Dimers of phenol in argon and neon matrices

Abstract

The IR absorption spectra of phenol molecules in solid rare gas matrices of argon (10–12 K) and neon (4.5–5 K) are investigated at molar ratios of phenol:matrix of 1:1000 to 1:30 in the frequency range 400–4000 cm−1. Bands of dimers and larger complexes of phenol molecules are observed in the absorption spectrum of both matrices as the matrix ratio decreases. The first additional bands to appear in the spectral region of the stretching vibrations of the O–H group as the phenol concentration increases are two bands attributed to dimers with one and two hydrogen bonds. The absorption coefficients are determined for the bands of stretching vibrations of the O–H and C–O groups, O–H planar bending vibrations of monomers, and the stretching vibrations of the hydrogen-bonded O–H groups of the phenol molecules. The features of the formation of H-bonded complexes in low-temperature matrices are discussed. A model is proposed which permits calculation of the number of monomers, dimers, and larger complexes in argon and neon matrices for molecules which are close in size to the phenol molecule.