Effect of molecular interactions on the O-H stretching force constants for associated water species
✍ Scribed by R. Brakaspathy; Surjit Singh
- Publisher
- Elsevier Science
- Year
- 1986
- Tongue
- English
- Weight
- 349 KB
- Volume
- 131
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Semi-empirical molecular-orbital calculations are reported for the O-H stretching force constants of different hydrogen-bonded species of water involving dimeric, trimeric, tetrameric and pentameric associations. These calculations show that -in general -a water molecule bonded to another water molecule through oxygen lone-pair electrons behaves as a stronger acid than an isolated water molecule, and a water molecule bonded to two water molecules through its two oxygen lone pairs is still stronger. This is reflected in the force constants of hydrogen-bonded O-H bonds. These results explain why O-H stretching bands in IR and Raman spectra of liquid water appear at significantly lower frequencies than for solutions of water in organic bases, even though water is a weaker base.