Fitting Complex Potential Energy Surfaces to Simple Model Potentials: Application of the Simplex-Annealing Method

RAÚL A. BUSTOS MARÚN; EDUARDO A. CORONADO; JUAN C. FERRERO

JOHN WILEY & SONS INC

Año: 2005 vol. 26 p. 523 - 523

A stochastic method of optimization, which combines simulated annealing with simplex is implemented to fit the parameters of a simple model potential. The main characteristic of the method is that it explores the whole space of the parameters of the model potential and therefore it is very efficient in locating the global minimum of the cost function, in addition of being independent of the initial guess of the parameters. The method is employed to fit the complex intermolecular potential energy surface of the dimer of water, using as reference the spectroscopic quality anisotropic site-site potential of Feller et al. [Science 284, 945 (1999)]. The simple model potential chosen for its re-parameterization is the MCY model potential of Clementi et al. [J. Chem. Phys. 64, 1351 (1976)]. The quality of the fit is assessed by comparing the geometry of the minimum, the harmonic frequencies, and the second virial coefficients of the parameterized potential with the reference one. Finally,