ISSN:
0020-7608
Schlagwort(e):
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Calculations have been carried out on small linear water chains in order to investigate nonadditivity and cooperativity effects and to study the rate of convergence of the many-body interaction potential. Ab initio wave functions were computed for the pentamer and all related subgroups by using the self-consistent, nonorthogonal group function approximation. The interaction energy and its electrostatic, exchange, polarization, and charge-transfer components were decomposed into a sum of n-body terms. Simple formulas were developed for estimating the interaction energy of higher-order complexes, which also allow an extrapolation to be made to infinite chain length. Comparison of the extrapolated interaction energies, with and without including the nonadditivity effects, showed that the latter increases the H-bond's stability by more than 25%. The results further suggest that the interaction potential can be truncated at either the three- or four-body level, depending on the accuracy required, but that, at best, only rough qualitative results can be expected when pair additivity is assumed. Finally, the dipole moment appears to be sufficiently converged with the inclusion of trimeric terms.
Zusätzliches Material:
5 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/qua.560290406
