First-principles vibrational studies of pentaerythritol crystal under hydrostatic pressure

First-principles calculations for the vibrational frequencies of the pentaerythritol crystal are presented, at ambient and hydrostatic pressure. The Crystal03 program with the Hartree-Fock potential and B3LYP density functional were used with 6-31G and 6-31G∗∗ basis sets, respectively. The calculated OH stretching mode vibrational frequencies using this approach are about 200 cm−1 lower using Crystal03 than those calculated using the Gaussian98 program. The effect of hydrostatic pressure on vibrational frequencies is calculated and compared with experimental data, up to 4 GPa. The OH-stretching mode frequency decreased as a function of increasing pressure, in agreement with experiment.