Quantum statistical mechanics via the recursive residue generation method

Using the recursive residue generation method (RRGM), it is shown how Green’s function matrix elements calculated in large basis sets (N≫103) can be utilized to obtain controlled approximations to average values, correlation functions, and power spectra in multimode anharmonic systems. Convergence of the method is demonstrated through studies on five and seven mode model systems with basis sets containing up to about 8×103 states.