Kleist Elyse M, Koch Dandolo Corinna L, Guillet Jean-Paul, Mounaix Patrick, Korter Timothy M
Department of Chemistry , Syracuse University , Syracuse , New York 13244 , United States.
IMS Laboratory, UMR CNRS 5218 , University of Bordeaux , 351 cours de la liberation , 33405 Talence , France.
J Phys Chem A. 2019 Feb 14;123(6):1225-1232. doi: 10.1021/acs.jpca.8b11676. Epub 2019 Feb 4.
Terahertz spectroscopy, a noninvasive and nondestructive analytical technique used in art conservation and restoration, can provide compelling data concerning the composition and condition of culturally valuable and historical objects. Terahertz spectral databases of modern and ancient artists' pigments exist but lack explanations for the origins of the unique spectral features. Solid-state density functional theory simulations can provide insight into the molecular and intermolecular forces that dominate the observed absorption features as well as reveal deviations from simple harmonic vibrational behavior that can complicate these spectra. The characteristic terahertz spectra of solid azurite, malachite, and verdigris are presented here, along with simulations of their crystalline structures and sub-3.0 THz lattice vibrations. The powerful combination of theory and experiment enables unambiguous spectral assignment of these complex materials and highlights the challenges that anharmonic peak broadening in organic-containing materials may present in the construction of reference pigment databases.
太赫兹光谱学是一种用于艺术品保护和修复的非侵入性、非破坏性分析技术，它可以提供有关具有文化价值和历史意义的物品的成分和状况的有力数据。现代和古代艺术家颜料的太赫兹光谱数据库已经存在，但缺乏对独特光谱特征起源的解释。固态密度泛函理论模拟可以深入了解主导观察到的吸收特征的分子和分子间作用力，还能揭示与简单谐波振动行为的偏差，这些偏差会使这些光谱变得复杂。本文展示了固态蓝铜矿、孔雀石和铜绿的特征太赫兹光谱，以及它们晶体结构和低于3.0太赫兹晶格振动的模拟。理论与实验的强大结合使得能够对这些复杂材料进行明确的光谱归属，并突出了含有机材料中的非谐峰展宽在构建参考颜料数据库时可能带来的挑战。
