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.