"Substituent Effects on Dynamics at Conical Intersections: Cyclopentadienes" Oliver Schalk, Andrey E. Boguslavskiy, Albert Stolow
J. Phys. Chem. A, 114, 4058 (2010).
Abstract: Substituent effects on dynamics at conical intersections are investigated by means of femtosecond timeresolved
photoelectron spectroscopy for cyclopentadiene and its substituted analogues 1,2,3,4-tetramethylcyclopentadiene,
1,2,3,4,5-pentamethylcyclopentadiene, and 1,2,3,4-tetramethyl-5-propylcyclopentadiene. By
UV excitation to the S2 (11B2) state, the influence of these substitutions on dynamics for the initially excited
S2 (11B2) surface and the spectroscopically dark S1 (21A1) surface were investigated. We observed that the
dynamics depend only on a small number of specific vibrations. Whereas dynamics at the S2/S1-conical
intersection are independent of substitution at the 5-position, internal conversion dynamics on the S1 (21A1)
surface slow down as the inertia of the 5-substituent increases. Contrary to the expectations of simple models
of radiationless transitions, an increasing density of states does not lead to faster processes, suggesting that
a true dynamical picture of vibrational motions at conical intersections will be required.
This publication has not been written at BMO
BMO authors (in alphabetic order): Oliver Schalk
WWW-Version
|