HIGHLY EXCITED VIBRATIONAL-STATES OF LARGE MOLECULES BY THE METHOD OF TRIATOMIC FRAGMENTS IN MOLECULES

Triatomic fragments in molecules (TAFIM) is a general method for calculating highly excited vibrational states of molecules of any size. By use of a graph theoretical procedure, the molecule under consideration is split formally into all possible triatomic fragments connected by two adjacent bonds. A minimized set of basis functions for each bond in all fragments is obtained by application of a reduction method. By taking the conjunction of those reduced bond basis sets, the basis set for the whole molecule is formed. Within this basis, the molecular Schrödinger equation is solved by transforming it into an algebraic eigenvalue problem. © 1990 American Chemical Society.