SINGLE-CRYSTAL POLARIZED SPECTRA IN THE NEAR-INFRARED REGION - A LOCAL-MODE ANALYSIS OF THE SPECTRA OF BACL2.2H2O

The near-infrared (near-IR) spectra of single crystals of BaCl2-2H2O and its partially deuterated analogue have been recorded at 10 K in polarized light. Two crystallographically independent water molecules are present in these crystals. Each water gives rise to numerous, often well-resolved overtone and combination features. The bands in the first and second stretch overtone regions were analyzed by using local-mode theory. The local-mode anharmonicity, X, and harmonic frequency, ω, were evaluated for each of the oscillators on the two water molecules, as well as the two local-mode coupling constants, λ. The local-mode parameters so obtained are substantially altered from the values reported for gas-phase water. This is a consequence of hydrogen-bond formation in the crystal. © 1990, American Chemical Society. All rights reserved.