Raman Spectra of Pinacol Hexahydrate in the Region of OH Stretches at Room Temperature

Abstract

The polarized Raman spectra of pinacol hexahydrate (PHH) and 5% deuterated PHH were observed at room temperature in the region of the O–H and the decoupled O–D stretches, respectively. The decoupled O–D stretches were assigned on the basis of there being four kinds of hydrogen bond. The polarized Raman spectra of PHH were analysed using 108 water and 18 pinacol molecules with disorder in the hydrogen positions which satisfy a periodic boundary condition. The observed Raman spectra were explained well using the initial set of force constants with the exception of the intermolecular interaction constants. The observed Raman spectrum of deuterated PHH in the polycrystalline state was also reproduced well. The wavenumber of the in-phase ν1 mode of PHH and the intermolecular interaction constant are noticeably larger than those for related compounds.