Picosecond absorption spectra of the second excited singlet state of a molecule in the condensed phase: Xanthione

✍ Scribed by R.W. Anderson Jr.; R.M. Hochstrasser; H.J. Pownall

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 513 KB
• Volume: 43
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(76)85290-6

✦ Synopsis

The fluorescence emission from the S2 state of xanthione in benzene solution was time resolved using a Nd3' glass mode-locked laser driven light gate technique. Using a separate optical apparatus, in conjunction with the mode-locked laser, transient absorption spectta were recorded at times subsequent to excitation. In both experiments excitation was provided by the 353 nm third harmonic of the neodymium laser. The exponential lifetime of the S2 fluorescence lvas found to be 12 2 3 ps. Two distinct transient absorption bands appear as a function of time after excitation. At early times a band centered at 620 nm is observed which we ascribe to absorption from S2 while at ionger times a band at 540 nm appears. This latter transient persists for up to 2 ns and we assign this band to absorption from T1.