PATH-INTEGRAL MONTE-CARLO STUDY OF CRYSTALLINE LENNARD-JONES SYSTEMS

The capability of the path-integral Monte Carlo (PIMC) method to describe thermodynamic and structural properties of solids at low temperatures is studied in detail, considering the noble-gas crystals as examples. In order to reduce the systematic limitations due to finite Trotter number and finite particle number we propose a combined Trotter and finite-size scaling. As a special application of the PIMC method we investigate Ar40 at constant volume and in the harmonic approximation. Furthermore, isotope effects in the lattice constant of Ne20 and Ne22 are computed at zero pressure. The obtained results are compared with classical Monte Carlo results and with experimental data. © 1995 The American Physical Society.