Theoretical study on second hyperpolarizability of H3+ system by path integral method

Based on the path integral method formulated in terms of the Thouless parametrization, numerical calculations of the ensemble average of the polarizability and the second hyperpolarizability are carried out by means of the Monte Carlo method. An H3+ system is examined to elucidate the performance of the present method. We discuss the dependence of the calculated (hyper)polarizabilities on the number of the division of the partition function and the accuracy of the results obtained by the present method.