Resonance Raman spectrum of β‐carotene

Abstract

Resonance Raman spectra for j?-carotene in carbon disulphide at room temperature have been measured. The experimental absorption spectrum and excitation profiles were analysed using a three-dimensional model involving several molecular parameters related to the excited state's structure. These parameters are quite different from those reported previously in the literature. A possible explanation for this disaepancy is proposed.

Raman excitation profiles of β ‐carotene – novel insights into the nature of the ν1‐band

“…Intensities have been normalized using the Raman peak of dichloromethane at 1423 cm −1 as an internal standard. From these intensities the resonance excitation profiles can be derived as reported previously [5,6]. The band position seems to show a reproducible dependence on the excitation wavelength varying for example from 1521 cm −1 at 413 nm excitation to 1525 cm −1 at 476 nm excitation.…”

“…The Raman spectra of β-carotene shows three prominent vibrational bands named ν 1 , ν 2 and ν 3 (at 1524, 1157 and 1005 cm −1 , respectively), which are attributed to the double bond C=C stretching mode (1524 cm −1 ), the C-C in-plane single bond stretching mode (1157 cm −1 ), and the C-H bending mode (1008 cm −1 ), respectively [5][6][7]. For all three bands resonance Raman excitation profiles of isolated β-carotene have been studied in the past [3,8].…”

Study of carotenoids in cyanobacteria by Raman spectroscopy

“…The preferential cellular localization of β-carotene is inside of the thylakoid membranes, while the cytoplasmic membranes provide preferential location for xanthophyll compounds [15]. Carotenoids are a very special family consisting over 400 conjugated polyenes with C40 substituted and unsubstituted/unsaturated carbon-carbon chains and, jointly with chlorophyll compounds, are responsible for radiation absorptions, mainly in the visible region of the electromagnetic spectrum [33,[50][51][52][53]. The Raman spectra profile of these type of polyunsaturated chain present three characteristic bands located at specific wavenumbers, in the region between 1600-1000 cm -1 which are definitive data for those pigments characterization by Raman spectroscopy [38,39,43,54,55].…”

Self-consistent-field calculations of the vibrational spectrum of undoped and doped transpolyacetylene

“…The latest calculation by Suhai (10) shows that the inclusion of correlation effects reduces the bond length alternation compared to the in the investigation of the chemical properties and structure of undoped and doped PA (15)(16)(17)(18). However, they cannot provide a complete and conclusive answer to the question whether the ground-state structure is equidistant or alternant.…”