Terahertz spectroscopy and lattice vibrational analysis of pararealgar and orpiment

• Published in: Chinese physics B Vol. 31; no. 10; pp. 103302 - 436
• Main Authors: Zhang, Ya-Wei, Ren, Guan-Hua, Su, Xiao-Qiang, Meng, Tian-Hua, Zhao, Guo-Zhong
• Format: Journal Article
• Language: English
• Published: Chinese Physical Society and IOP Publishing Ltd 01.10.2022; Institute of History for the Science and Technology,Inner Mongolia Normal University,Hohhot 010022,China; School of Yungang Ology,Shanxi Datong University,Datong 037009,China%Department of Mathematics and Physics,North China Electric Power University,Baoding 071003,China%Institute of Solid State Physics,Shanxi Provincial Key Laboratory of Microstructure Electromagnetic Functional Materials,Shanxi Datong University,Datong 037009,China%Department of Physics,Capital Normal University,Beijing 100048,China
• Subjects: lattice vibrations; orpiment; pararealgar; solid-state density functional theory (ss-DFT); THz-TDS; orpiment; THz-TDS; pararealgar; solid-state density functional theory(ss-DFT); lattice vibrations
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/ac7cd3

Terahertz time-domain spectroscopy (THz-TDS) is an effective nondestructive and noninvasive tool for investigating sulfur-containing pigments. Combined with Raman spectroscopy and vibrational mode analysis, it is significant for artifact identification and conservation. In this work, the terahertz absorption spectra of pararealgar (As 4 S 4 ) and orpiment (As 2 S 3 ) samples mixed with polytetrafluoroethylene (PTFE) are characterized in a range from 0.2 THz to 2.2 THz, and their distinctive peaks are observed, respectively. Meanwhile, qualitative analysis is also implemented by using Raman spectroscopy as a complementary technique. The lattice vibrations are simulated by using solid-state density functional theory (ss-DFT), illustrating different characteristic absorption peaks for specific crystalline structures and dynamic properties. This work provides a reliable database of sulfur-containing pigments for using the THz technology to actually analyze and diagnose cultural relics.