A modified genetic algorithm with real-number coding, non-uniform mutation and arithmetical crossover operators was described in this paper. A local minimization was used to improve the final solution obtained by the genetic algorithm. Using the exp-6-1 interatomic energy function, the modified genetic algorithm with local minimization (MGALM) was applied to the geometry optimization problem of small benzene clusters (C6H6)N(N = 2-7) to obtain the global minimum energy structures. MGALM is simple but the structures optimized are comparable to the published results obtained by parallel genetic algorithms.
Systematic studies are made on application of chemometrics to chemical modeling and/or molecular modeling as well as the regularity of retention index for gas chromatography (GC). A set of novel molecular graph theoretical parameters, called the molecular distance-edge (MDE) vector (λ), is proposed and found to be excellently correlated to retention index of GC for alkanes. The MDE parameters were tested by the multiple linear regression (MLR) estimation and prediction of the retention index of GC, and the results obtained are satisfactory.
