Investigating the low-frequency vibrations of chlorophyll derivatives using terahertz spectroscopy

Dominique Coquillat (1) , Emma O'Connor (2) , Etienne Brouillet (2) , Yoann Meriguet (1, 3) , Cédric Bray (1) , David J. Nelson (2) , Karen Faulds (2) , Jeremie Torres (3, 4) , Nina Diakonova (1)

1 L2C - Laboratoire Charles Coulomb
2 University of Strathclyde [Glasgow]
3 IES - Institut d’Electronique et des Systèmes
4 MOST - Modélisation et Spectroscopie THz

The terahertz absorption spectra of sodium magnesium chlorophyllin (Chl-Mg-Na) and sodium copper chlorophyllin (Cu-Chl), two major members of the chlorophyll derivative family, have been measured in the range 0.2−3.0 THz (6.6−100 cm-1), at room temperature. Additionally, surface-enhanced Raman scattering spectroscopy was used to supplement data in the higher frequency range. The capability of terahertz spectroscopy for quantitative characterization of Chl-Mg-Na intermolecular vibrations was investigated and the sensitivity of the 1.82-THz feature with degree of hydration by changes in the molecular environment was examined. For Cu-Chl derivative, a broad feature was observed around 1.8 THz which currently hinders clear Cu-Chl identification and quantification.

Mots clés: TerahertzChlorophyllintermolecular vibrational modes

Domaines: Physique Générale [physics.gen-ph]

Dominique Coquillat, Emma O'Connor, Etienne Brouillet, Yoann Meriguet, Cédric Bray, et al.. Investigating the low-frequency vibrations of chlorophyll derivatives using terahertz spectroscopy. SPIE Optical Engineering + Applications, 2021, San Diego, California, United States, Aug 2021, San Diego, United States. pp.118270F, ⟨10.1117/12.2593589⟩. ⟨hal-03406165⟩