Poster Presentation 23rd International Society of Magnetic Resonance Conference 2023

Solid-state 207Pb NMR spectroscopy and relativistic quantum chemical calculations of red pigments in cultural heritage materials (#320)

Takahiro Iijima 1 , Takahiro Abe 1 , Kenzo Deguchi 2 , Shinobu Ohki 2 , Masataka Tansho 2
  1. Yamagata University, Yamagata, Japan
  2. National Institute for Materials Science, Tsukuba, Japan

Solid-state 207Pb NMR spectroscopy was used to identify the pigments painted on the surface of a cultural heritage material. The 207Pb NMR magic-angle-spinning spectrum was measured under 18.8 T for the 1.0% lead containing pigment sample of a historical clay doll. By comparing with the reference spectrum and NMR parameters, minimum (Pb3O4) was determined to be used as a red pigment in the doll. Further, spectral simulation and relativistic density functional theory calculations were carried out for Pb3O4 and related compounds. It was confirmed for the large chemical shift anisotropy of the PbII species with the hemi-directed structure that the calculations with the minimum PbOn moiety can generate incorrect values and that large size clusters are needed for improving accuracy even with the fully relativistic method.