Ultrafast Deactivation of the ππ(V) State of Ethylene Studied Using Sub-20 fs Time-Resolved Photoelectron Imaging

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 119; no. 36; pp. 9518 - 9523
• Main Authors: Kobayashi, Takufumi, Horio, Takuya, Suzuki, Toshinori
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10.09.2015
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/acs.jpca.5b06094

The ultrafast deactivation process of ethylene in the ππ*­(V) state was studied using time-resolved photoelectron imaging with sub-20 fs pulses at 159 and 198 nm. The photoelectron kinetic energy distribution observed upon 159 nm photoexcitation exhibited a continuous downward shift within 20 fs, attributed to both C–C twist and pyramidalization motions. A partial revival of the vibrational wave packet was observed with the period of about 18 fs, which is attributed to the C–C twist from 0 to 180° on the ππ*­(V) potential energy surface. Signature for internal conversion from the ππ*­(V) state to a lower-lying π3s Rydberg (R) state, which has been previously suggested, was not detected in the time-dependent photoelectron kinetic energy and angular distributions.