Path Integral Monte Carlo Study of X@C50 [X=H2, He, Ne, Ar

Abstract

Path integral Monte Carlo (PIMC) method is employed to study the thermal properties of the X@C50[X=H2, He, Ne, Ar] system at temperatures from 5K to 300 K. The interaction energies and probability distribution functions of one noble gas atom or H2 inside D5h-symmetry C50 are obtained. A rough sphere model is used in calculating interaction energies, as a comparison. This model gives much lower interaction energy than PIMC calculations on all X@C50, except He@C50. The PIMC method and the sphere model get nearly the same values of interaction energies on He@C50. The spatial distributions are enlarged by the increase in temperature, while the interaction energies change slowly in a wide range of temperature. Temperature is not the major reason for the stability of the system. It is impossible to trap an X atom into C50, except H2 because only the H2@C50 has positive interaction energies from the PIMC calculations.