Vibrational spectrum of PETN investigated in terahertz range

Abstract

Although the experimental solid-state terahertz (THz) spectrum (0.2-2.5THz) of the high explosive petaerythritol tetranitrate (PETN, C₅H₈N₄O₁₂) has been presented previously, till now, the theoretical analysis of its THz spectrum is few reported before. In this paper, we used solid-state density functional theory (DFT) calculation to simulate the vibrational spectrum of PETN in THz range. The DFT calculations were performed using DMol³ (version 4.0). Solid-state DFT, employing the BP density functional, can be able to reproduce the experimentally observed solid-state structure and low-frequency vibrational motions, and final simulated spectrum has a good-to-excellent agreement with experimental THz spectrum. In order to observe more THz spectrum details of PETN, we increased the frequency-domain resolution. Furthermore, we also have obtained the refractive index, absorption coefficient of this sample by THz time-domain spectroscopy.