Three different kinds of condensed samples of all-trans-(beta) -carotene, i.e., a spin-coated film, a cast film, and crystals, were prepared. Excitation spectra of photoconductivity at room temperature and resonance Raman scattering at 11 K were obtained for these samples, and the influence of oxygen to these excitation spectra were examined. In the near infrared region below the lowest allowed transition to the electronically excited ¹B_u state, clear bands were observed in those two kinds of excitation spectra and were characteristic of the crystals as well as the cast film. The excitation bands are attributable to the same transition to the 2¹Ag molecular exciton state. A similar series of experiments were carried out for all-trans-(beta) -apo-8'-carotenal. The results support the above assignment for all-trans- (beta) -carotene.

Date Published: 9 February 1995
PDF: 9 pages
Proc. SPIE 2362, International Conference on Excitonic Processes in Condensed Matter, (9 February 1995); doi: 10.1117/12.200954

Published in SPIE Proceedings Vol. 2362:
International Conference on Excitonic Processes in Condensed Matter
Jai Singh, Editor(s)