AN EMPIRICALLY ADJUSTED NEWTON-RAPHSON ALGORITHM FOR FINDING LOCAL MINIMA ON MOLECULAR-POTENTIAL ENERGY SURFACES

A simple extension of the Newton–Raphson method is proposed that approximately accounts for anharmonicity in bond‐stretching coordinates. By modeling each bonded distance in a polyatomic molecule as a Morse oscillator with no anharmonic stretch‐stretch or stretch‐bend coupling, a multiplicative correction factor to the Newton–Raphson step is derived. Representative examples suggest that the rate of convergence of the proposed scheme is typically faster than that of the standard Newton–Raphson method. Copyright © 1990 John Wiley & Sons, Inc.