Skip to main content

Research Repository

Advanced Search

Ultrafast dynamics of formation and autodetachment of a dipole-bound state in an open-shell π-stacked dimer anion

Bull, J.N.; West, C.W.; Verlet, J.R.R.

Ultrafast dynamics of formation and autodetachment of a dipole-bound state in an open-shell π-stacked dimer anion Thumbnail


Authors

J.N. Bull

C.W. West



Abstract

Isolated π-stacked dimer radical anions present the simplest model of an excess electron in a π-stacked environment. Here, frequency-, angle-, and time-resolved photoelectron imaging together with electronic structure calculations have been used to characterise the π-stacked coenzyme Q0 dimer radical anion and its exited state dynamics. In the ground electronic state, the excess electron is localised on one monomer with a planar para-quinone ring, which is solvated by the second monomer in which carbonyl groups are bent out of the para-quinone ring plane. Through the π-stacking interaction, the dimer anion exhibits a number of charge-transfer (intermolecular) valence-localised resonances situated in the detachment continuum that undergo efficient internal conversion to a cluster dipole-bound state (DBS) on a ∼60 fs timescale. In turn, the DBS undergoes vibration-mediated autodetachment on a 2.0 ± 0.2 ps timescale. Experimental vibrational structure and supporting calculations assign the intermolecular dynamics to be facilitated by vibrational wagging modes of the carbonyl groups on the non-planar monomer. At photon energies ∼0.6–1.0 eV above the detachment threshold, a competition between photoexcitation of an intermolecular resonance leading to the DBS, and photoexcitation of an intramolecular resonance leading to monomer-like dynamics further illustrates the π-stacking specific dynamics. Overall, this study provides the first direct observation of both internal conversion of resonances into a DBS, and characterisation of a vibration-mediated autodetachment in real-time.

Citation

Bull, J., West, C., & Verlet, J. (2016). Ultrafast dynamics of formation and autodetachment of a dipole-bound state in an open-shell π-stacked dimer anion. Chemical Science, 7(8), 5352-5361. https://doi.org/10.1039/c6sc01062h

Journal Article Type Article
Acceptance Date Apr 23, 2016
Online Publication Date May 4, 2016
Publication Date Aug 1, 2016
Deposit Date Jun 14, 2016
Publicly Available Date Mar 28, 2024
Journal Chemical Science
Print ISSN 2041-6520
Electronic ISSN 2041-6539
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 7
Issue 8
Pages 5352-5361
DOI https://doi.org/10.1039/c6sc01062h

Files






You might also like



Downloadable Citations