Feynman path-integral Monte Carlo simulations of crystalline silicon,
using the empirical potential of Stillinger and Weber, have been perfo
rmed in the isothermal-isobaric ensemble. Several thermodynamic proper
ties have been evaluated as a function of pressure and temperature. Th
e calculated lattice parameter, heat capacity, thermal expansion coeff
icient, and bulk modulus show an overall agreement with the experiment
al data. However, the negative thermal expansion of silicon at tempera
tures below 120 K is not reproduced with this model potential. The imp
ortance of anharmonicity and quantum effects on the properties derived
from the Stillinger-Weber potential is addressed by comparison with t
he results expected in a quasiharmonic approximation and in the classi
cal limit.