Electronic relaxation processes of all-trans-2,4,6,8-decatetraene vapour revealed by the measurements of the S1 and S2 fluorescence

Itoh Takao

Molecular Physics

Fluorescence and excitation spectra of all-trans-2,4,6,8-decatetraene vapour have been measured at different buffer gas pressures from 0 to 1.07 x 105 Pa (800 Torr). The quantum yield of the S1 fluorescence (phi F(S1)) increases with increasing the buffer gas pressure, while that of the S2 fluorescence (phi F(S2)) decreases slightly. phi F(S1) decreases significantly with increasing the excitation energy under the collision free condition, while phi F(S2) decreases only slightly. The pressure dependence of the fluorescence yields is interpreted in terms of the relaxation model involving the reversible internal conversion between S1 and S2 and the vibrational relaxation in the S1 manifold. The reverse S1 S2 internal conversion rate is shown to be very slow compared with the forward S2 S1 internal conversion rate.

decatetraene vapour

excited states

S2 fluorescence

electronic relaxation

Physics [ 420 ]

eng

Taylor & Francis Ltd

Copyright (c) 2009 Taylor & Francis "This is an electronic version of an article published in Molecular Physics Vol.107 No.16 pp.1705-1711 2009. Molecular Physics is available online at http://dx.doi.org/10.1080/00268970903029115"

[ISSN] 0026-8976

[DOI] 10.1080/00268970903029115

[NCID] AA00745902

[DOI] http://dx.doi.org/10.1080/00268970903029115