Abstract
AbstractTetradesmethyl‐β‐carotene is found to form aggregates in a mixed solvent of methylcyclohexane and isopentane at temperatures below 180 K. The absorption band around 470 nm (0–0 transition) of the monomer splits into a pair of absorptions (exciton bands) on aggregation, one around 400 nm and the other around 500 nm. Four Raman bands are observed at about 1520 (ν1), 1130 (ν2), 1600 (νa) and 1570 (νb) cm−1 for the aggregate, two of them (ν1 and ν2) being observed with strong intensities also in the Raman spectrum of the monomer. The ν1 and ν2 bands are observed with exciting radiation in resonance with either one of the two absorptions of the aggregate, whereas the intensities of the other two Raman bands (νa and νb) are enhanced only in resonance with the absorption around 400 nm. These results are discussed in terms of vibronic coupling involving a forbidden singlet state in the near‐ultraviolet region.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
