Picosecond absorption spectra of the second excited singlet state of a molecule in the condensed phase: Xanthione |
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Authors: | RW Anderson RM Hochstrasser HJ Pownall |
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Institution: | Department of Chemistry and Laboratory for Research on the Structure of Matter, University of Pennyslvania, Philadephia, Pennsylvania 19174, USA;Baylor College of Medicine, Texas Medical Center, Houston, Texas 77025, USA |
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Abstract: | The flourescence emission from the S2 state of xanthione in benzene solution was time resolved using a Nd3+ glass mode-locker laser driven light gate technique. Using a separate optical apparatus, in conjunction with the mode-locked laser, transient absorption spectra 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 flourescence was found to be 12±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 longer 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. |
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Keywords: | Permanent affiliation and supporting institution: Pitman-Dunn Laboratories Frankford Arsenal Philadelphia Pennsylvania USA |
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