Two-photon absorption spectrum of all-trans retinal

✍ Scribed by Shoichi Yamaguchi; Tahei Tahara

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 272 KB
• Volume: 376
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/s0009-2614(03)00984-9

✦ Synopsis

The nondegenerate two-photon absorption spectrum of all-trans retinal in a nonpolar solvent at room temperature has been measured for the first time. The multichannel detection utilizing the technique of femtosecond time-resolved pump-probe absorption spectroscopy has enabled us to obtain precise two-photon absorption spectra. It was found that the two-photon absorption maximum of all-trans retinal is located at 376 nm, which is 7 nm longer than the onephoton absorption peak. This peak wavelength difference indicates the 500-cm À1 energy gap between the S 3 (B u ) state and the S 2 (A g ) state. On the basis of the obtained two-photon absorption data and the available fluorescence data, we determined the 0-0 position of the S 2 state to be 2.47 Â 10 4 cm À1 .