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Terahertz Analysis of Phthalocyanine Pigments

Journal Article


Abstract


  • In situ, non-invasive and non-destructive analysis of important artworks and cultural pieces is largely important in art conservation science. Terahertz time-domain spectroscopy and imaging delivers these requirements but lacks a materials database with fundamental understanding of salient pigments, binders and substrates. In this study, the most important synthetic pigments, the copper phthalocyanines, are investigated through terahertz time-domain spectroscopy. The terahertz spectrum reveals a series of characteristic modes in a 0.1–3-THz range across 14 pigment samples. Identification and distinction of copper phthalocyanines’ α, β and ? crystal polymorphs is demonstrated. This uniqueness within the terahertz regime is extended to two halogenated variants and a metal-free form. This invites the use of THz spectroscopy in investigation of contemporary artworks, post 1935, containing these pigments and promotes applications such as identifying fraudulent works of art.

Authors


Publication Date


  • 2019

Citation


  • Squires, A. D. & Lewis, R. A. (2019). Terahertz Analysis of Phthalocyanine Pigments. Journal of Infrared, Millimeter, and Terahertz Waves, 40 (7), 738-751.

Scopus Eid


  • 2-s2.0-85066123930

Number Of Pages


  • 13

Start Page


  • 738

End Page


  • 751

Volume


  • 40

Issue


  • 7

Place Of Publication


  • United States

Abstract


  • In situ, non-invasive and non-destructive analysis of important artworks and cultural pieces is largely important in art conservation science. Terahertz time-domain spectroscopy and imaging delivers these requirements but lacks a materials database with fundamental understanding of salient pigments, binders and substrates. In this study, the most important synthetic pigments, the copper phthalocyanines, are investigated through terahertz time-domain spectroscopy. The terahertz spectrum reveals a series of characteristic modes in a 0.1–3-THz range across 14 pigment samples. Identification and distinction of copper phthalocyanines’ α, β and ? crystal polymorphs is demonstrated. This uniqueness within the terahertz regime is extended to two halogenated variants and a metal-free form. This invites the use of THz spectroscopy in investigation of contemporary artworks, post 1935, containing these pigments and promotes applications such as identifying fraudulent works of art.

Authors


Publication Date


  • 2019

Citation


  • Squires, A. D. & Lewis, R. A. (2019). Terahertz Analysis of Phthalocyanine Pigments. Journal of Infrared, Millimeter, and Terahertz Waves, 40 (7), 738-751.

Scopus Eid


  • 2-s2.0-85066123930

Number Of Pages


  • 13

Start Page


  • 738

End Page


  • 751

Volume


  • 40

Issue


  • 7

Place Of Publication


  • United States