Quantum-Monte Carlo study of rovibrational states of molecular systems

A novel procedure to calculate the excited rovibrational energy levels of quantum-molecular systems based on the correlation-function quantum-Monte Carlo (CFQMC) method is proposed. The procedure utilizes rotating wavefunctions as the trial basis in the CFQMC method. We test the present methodology in two low-dimensional systems: a rotating harmonic oscillator and rotating Morse potential. Comparisons are made with numerical `exactʹ results and they are shown to be accurate.