Path integral simulation of hydrogen adsorption in single-walled carbon nanotubes at low temperatures
Abstract
Path integral Monte Carlo simulation (PIMC) in the canonical ensemble is applied to study hydrogen properties at low temperatures. Energies, pressures and radial distribution functions are obtained. The simulation results of the quantum system are compared with those of the classical system at the same temperatures. It is found that at the temperature and pressure ranges studied, hydrogen molecules have significant quantum effects. In addition, two energy estimators in path integral simulation are compared. The phase diagram of bulk hydrogen is also calculated by PIMC in the Gibbs ensemble. Reasonable agreement between the calculated and experimental results is obtained. PIMC in the Gibbs ensemble is also used to calculate the phase separation of hydrogen in a