Spectroscopic investigation on the effect of gas adsorption on solid films of polyenes: Evidence of a low-lying forbidden transition

✍ Scribed by Krishnagopal Mandal; T.N. Misra

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 382 KB
• Volume: 27
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(74)80443-4

✦ Synopsis

Optical absorption spectra of a few polyenes in the crystalline state have been studied. On adsorption of certain gases on the crystallite surfaces of polyenes. a new band appears on the low energy side of the long wavelength bands of these polyenes. The position of this band is 536,537 and 375 m,u for all~runs &c:nrotene. 15,LS'sis O-carotene and retinyl compounds, respectively.

A good mirror image relationship between the new absorption bonds and the well known emission bands for these molecules indicates that this new band may be due to a weak transition to a low-lying n-electron state. This transition corresponds to a forbidden state below the strongly allowed (' Bu) state. The adsorbed gas molecules introduce the perturbation required for the enhancement of a low-lying forbidden transition.