Dimers of phenol in argon and neon matrices

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 phe nol: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 abso rption spectrum of both matrices as the matrix ratio decreases. The first a dditional bands to appear in the spectral region of the stretching vibratio ns of the O-H group as the phenol concentration increases are two bands att ributed to dimers with one and two hydrogen bonds. The absorption coefficie nts 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 vib rations of the hydrogen-bonded O-H groups of the phenol molecules. The feat ures 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 molec ules which are close in size to the phenol molecule. (C) 2001 American Inst itute of Physics.