AbstractA 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–Rap