Cr. Zacharias et al., COMBINING GENETIC ALGORITHM AND SIMULATED ANNEALING - A MOLECULAR-GEOMETRY OPTIMIZATION STUDY, Journal of molecular structure. Theochem, 430, 1998, pp. 29-39
We introduce a new hybrid approach to determine the ground state geome
try of molecular systems. Firstly, we compared the ability of genetic
algorithm (GA) and simulated annealing (SA) to find the lowest energy
geometry of silicon clusters with six and 10 atoms. This comparison sh
owed that GA exhibits fast initial convergence, but its performance de
teriorates as it approaches the desired global extreme. Interestingly,
SA showed a complementary convergence pattern, in addition to high ac
curacy. Our new procedure combines selected features from GA and SA to
achieve weak dependence on initial parameters, parallel search strate
gy, fast convergence and high accuracy. This hybrid algorithm outperfo
rms GA and SA by one order of magnitude for small silicon clusters (Si
b and Si lo) Next, we applied the hybrid method to study the geometry
of a 20-atom silicon cluster. It was able to find an original geometry
, apparently lower in energy than those previously described in litera
ture. In principle, our procedure can be applied successfully to any m
olecular system. (C) 1998 Elsevier Science B.V.