Vibrational spectroscopy and picosecond dynamics of gaseous trienes and tetraenes in S1 and S2 electronic states

摘要

Fluorescence excitation and emission spectra of the S$-1$/ and S$-2$/ states of model trienes and tetraenes are measured in free jet expansions. The barriers to cis-trans isomerization in the S$-1$/ state are $LS 200 cm$+$MIN@1$/ for trienes and approximately 2000 cm$+$MIN@1$/ for tetraenes. $LS 250 fs nonradiative decay of the S$-2$/ state of tetraenes is deduced from the observed Lorentzian linewidths.