Open AccessVIBRATION CHARACTERISTICS, CHEMICAL BONDS AND WEAK INTERACTIONS OF 4- AND 5-HYDROXYSALICYLIC ACID INVESTIGATED BY TERAHERTZ SPECTROSCOPY AND DENSITY FUNCTIONAL THEORY
Author(s) -
Yuan Yan Tang,
Zhi Li,
Yan Guo,
Yin X,
S.T. Tu,
David Zhang
Publication year - 2022
Publication title -
química nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.214
H-Index - 73
eISSN - 1678-7064
pISSN - 0100-4042
DOI - 10.21577/0100-4042.20170896
Subject(s) - terahertz radiation , density functional theory , van der waals force , intermolecular force , dihedral angle , hydrogen bond , spectroscopy , absorption (acoustics) , absorption spectroscopy , infrared spectroscopy , terahertz time domain spectroscopy , chemistry , terahertz spectroscopy and technology , materials science , molecular physics , analytical chemistry (journal) , computational chemistry , molecule , optics , physics , optoelectronics , organic chemistry , quantum mechanics , composite material
The terahertz (THz) absorption spectra of 4- and 5-hydroxysalicylic acid were measured by terahertz time-domain spectroscopy (THz-TDS) in the range of 0.4–2.8 THz. The unit cells of both were calculated by density functional theory (DFT), and the theoretical simulation and experimental data were basically in agreement. To further interpret the origin of the characteristic absorption peaks, vibration characteristics and interactions of the unit cell model were analyzed by using potential energy distribution (PED) and interaction region indicator (IRI) method. The analysis indicated that the absorption peaks of 4- and 5-hydroxysalicylic acid were mainly derived from the vibration mode of dihedral angle torsion, and were closely related to the hydrogen bonds. And the intermolecular weak interaction of both were mainly dominated in quantity by van der Waals interaction. The results show that this is an effective solution to identify isomers and explain the formation mechanism of characteristic absorption peaks by using THz-TDS and combining PED and IRI methods.