Large molecular systems: Computational modeling of geometry, force field parameters and intermolecular potential on a base of stable numerical methods

Abstract

This chapter provides an overview of the scheme of modeling vibrational spectra of the large size molecular systems based on stable numerical methods. New regularized algorithm for the determination of intermolecular potential U(R) on a base of second virial data B(T) is proposed. A priori information on convexity and monotonicity of potential U(R) at different distances R is also included in the regularization procedure. Mathematical formulation of the problem is reduced to minimization of a non-quadratic functional on a set of linear constraints defining a concave-convex potential function with the fixed inflection point. Position of inflection point is determined using enumerative techniques and the functional is minimized by the projection of conjugate gradients method.