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Time-resolved resonance Raman spectroscopy of diphenylacetylene: Structures and dynamics of the lowest excited triplet state, radical cation, and radical anion

Journal Article · · Journal of Physical Chemistry
Time-resolved resonance Raman spectra of the lowest excited triplet state, T{sub 1}, the radical cation, R{sup {sm_bullet}+}, and the radical anion, R{sup {sm_bullet}{minus}}, of diphenylacetylene (DPA) have been measured. Vibrational assignments of the Raman bands of these transients have been based on the frequency shifts on phenyl deuterations and {sup 13}C substitution of the C{triple_bond}C triple bond. The Raman spectra have shown that the C{triple_bond}C stretch exhibits large low-frequency shifts in the order, S{sub 0} (2217 cm{sup {minus}1}), R{sup {sm_bullet}+} (2142 cm{sup {minus}1}), R{sup {sm_bullet}{minus}} (2091 cm{sup {minus}1}), and T{sub 1} (1972 cm{sup {minus}1}), indicating that the C{triple_bond}C triple bond weakens dramatically in this sequence. The same trend, though not large, has been observed for phenyl skeletal vibrations as well. The dependence of the yield of R{sup {sm_bullet}+} on the pump laser power has revealed that the photoionization of DPA to produce R{sup {sm_bullet}+} is a biphotonic ionization can occur through the T{sub 1} state. 21 refs., 10 figs., 1 tab.
Sponsoring Organization:
USDOE
OSTI ID:
458811
Journal Information:
Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 22 Vol. 96; ISSN JPCHAX; ISSN 0022-3654
Country of Publication:
United States
Language:
English