GLOBAL MINIMA OF WATER CLUSTERS (H2O)(N), N-LESS-THAN-OR-EQUAL-TO-21,DESCRIBED BY AN EMPIRICAL POTENTIAL

Candidates are presented for the global minima of water clusters (H2O) (n), n less than or equal to 21, bound by the empirical rigid-body TIP 4P potential. The TIP4P global minima were subsequently relaxed subjec t to a more sophisticated model potential of the ASP family. Candidate s for the lowest energy 'box-kite' and dodecahedral minima of (H2O)(20 ) have also been obtained. For both the TIP4P and ASP potentials the l owest-lying dodecahedral isomers have much higher energies than the lo west-lying box-kite and face-sharing pentagonal prismatic minima, in c ontrast to the results of recent semi-empirical molecular orbital calc ulations. (C) 1998 Elsevier Science B.V.