ISSN:
1432-2234
Keywords:
Hydrogen bonds
;
Frequency shifts
;
Anharmonicity
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Calculations on the hydrogen-bonded complexes HCN⋯HF, H2O⋯HF, ClCN⋯HCl and (CH3)2O⋯HCl are reported. SCF harmonic values for the HF and HCl frequency shifts are in considerable disagreement with experiment, by as much as 100 cm−1. Calculations at the MP2 (harmonic) level yield improved agreement with experiment, reducing discrepancies to the order of 10 cm−1. We have also calculated all the cubic and quartic force constants for HCN⋯HF at the SCF level, so that the anharmonic constants, x rs can be evaluated. Although x 11 (v 1=H-F stretch) is large and negative, it is more than compensated by a positive x 16 (v 6=N⋯H-F bend), so that the anharmonic correction to v 1 is small and positive. The validity of these anharmonistudies is examined.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00538480
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