Measurement and DFT Calculation on Terahertz Spectroscopy of 4-aminobenzoic Acid
ABSTRACT We report the measurement of the terahertz (THz) spectra of 4-aminobenzoic acid by using Fourier transform infrared (FTIR)
spectroscopy in the 1.5–19.5THz. Low frequency intermolecular (or phonon) modes between 0.3 and 2.4THz were also investigated
via THz time-domain spectroscopy. Structure and vibrational frequencies of the sample were calculated through density functional
theory(DFT). The calculated results are in agreement with the experimental data. Moreover, we have interpreted observed vibrational
frequencies using DFT. Two intermolecular or phonon modes were identified at 1.54 and 2.19THz.