THEORETICAL SIMULATION OF OH AND OD STRETCHING BANDS OF ISOTOPICALLY DILUTED HDO MOLECULES IN AQUEOUS-SOLUTION
1993 (English)In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 171, no 1-2, 189-201 p.Article in journal (Refereed) Published
Uncoupled OH and OD stretching bands of HDO molecules have been calculated for an ionic aqueous solution, based on the trajectories from a classical statistical-mechanical computer simulation and subsequent quantum-mechanical calculations of the vibrational energy levels. Each V(r(OH)) potential function has been constructed as a sum of intra- and intermolecular energies, where different intermolecular water-water potential functions from the literature (MCY, TIPS2, RWK2 and CF2) have been tested in conjunction with the experimentally derived HMS intramolecular potential. In this way, vibrational densities-of-states as well as infrared absorption bands have been calculated for HDO molecules in the bulk and in the ionic hydration shells (Li+, HCOO-). Calculated frequencies and band widths for the TIPS2 and MCY potentials are fairly close to experimental values. The calculated OH shift between the gas and liquid water phases is - 303 cm-1 with the TIPS2 potential, as compared to the experimental value of - 307 cm-1. The MCY potential gives - 260 cm-1, while RWK2 as well as the CF2 potentials give rise to a non-negligible number of spurious frequencies. Water molecules in the first hydration shell of Li+ exhibit only slightly lower stretching frequencies than bulk water. The frequencies of the OH and OD groups of HDO molecules bonded to the formate oxygen atoms are lower than in bulk water, while the frequency of the OH/OD group pointing away from the formate ion is higher compared to bulk water.
Place, publisher, year, edition, pages
1993. Vol. 171, no 1-2, 189-201 p.
IdentifiersURN: urn:nbn:se:liu:diva-115184DOI: 10.1016/0301-0104(93)85143-VISI: A1993KV22300017OAI: oai:DiVA.org:liu-115184DiVA: diva2:794177