Terahertz Spectroscopy and Quantum Mechanical Simulations of Crystalline Historical Pigments

Terahertz spectroscopy is an excellent tool for the nondestructive and non-invasive investigation of pigments in historical and art objects. The characteristic terahertz spectra of solid azurite, malachite, and verdigris are presented here, along with fully quantum mechanical simulations of their crystalline structures and lattice vibrations. The powerful combination of theory and experiment enables unambiguous spectral assignments to be made in these complex materials, which allows for the improved construction of reference pigment databases.