INTRAMOLECULAR HYDROGEN-ATOM TUNNELING - ANALYTICAL SOLUTION FOR LINEAR COUPLING TO A LOW-FREQUENCY BATH

An analytical formula is derived for the tunneling splitting for a particle in a double-well potential linearly coupled to a low-frequency harmonic bath. Together with another previously developed treatment the formula can be used to interpret the tunneling splittings in molecules such as malonaldehyde or tropolone. The treatment is performed in terms of normal modes and can be incorporated into the usual normal-mode vibrational analysis. The formula is tested in comparison with numerical results from the literature for a particle in a double-well potential linearly coupled to a single low-frequency oscillator. Excellent agreement is obtained.