University of Illinois Urbana-Champaign

Rotation-tunneling analysis of proton-transfer dynamics in electronically excited 6-hydroxy-2-formylfulvene using degenerate four-wave mixing

Vealey, Zachary

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1092192.pptx
2976.pdf

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https://hdl.handle.net/2142/100809

Description

Title
Rotation-tunneling analysis of proton-transfer dynamics in electronically excited 6-hydroxy-2-formylfulvene using degenerate four-wave mixing
Author(s)
Vealey, Zachary
Contributor(s)
  • Vaccaro, Patrick
  • Foguel, Lidor
Issue Date
2018-06-21
Keyword(s)
Electronic structure, potential energy surfaces
Date of Ingest
  • 2018-08-17T16:09:48Z
  • 2018-12-12T22:36:48Z
Abstract
The multidimensional nature of classically hindered proton transfer is demonstrated clearly by the pronounced effects engendered by attendant electronic and vibrational degrees of freedom, the selective excitation of which can enhance or diminsh the rate of hydron migration greatly. To explore the provenance of such phenomena, the origin band (00 0 ) of the A˜1B2–X˜ 1A1 absorption system in 6-hydroxy-2-formylfulvene (HFF) has been probed under ambient bulk-gas conditions by using polarization-resolved degenerate four-wave mixing (DFWM) spectroscopy. The alleviation of rovibronic congestion and suppression of rotational-branch structure afforded by judicious selection of incident/detected polarizations for the DFWM interaction has enabled refined rotation-tunneling information to be extracted for the lowest-lying singlet excited manifold, A˜1B2 (π*π). In contrast to the ultrafast dynamics (τ pt≤120fs) that characterize the X˜ 1A1 ground electronic state of HFF, the π*←π electron promotion is found to impede intramolecular proton transfer markedly, leading to the near complete quenching of tunneling-induced spectral signatures. The intrinsic dependence of reaction coordinate and proton-transfer efficacy on the nuances of potential-surface topology and transition-state geometry will be discussed in light of these experimental results, with complementary quantum-chemical calculations serving to elucidate the dramatic impact that subtle changes in energy landscape can exert upon unimolecular dynamics.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/100809
DOI
10.15278/isms.2018.RJ01
Copyright and License Information
Copyright 2018 Zachary Vealey

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Abstracts & Presentations - 2018 International Symposium on Molecular Spectroscopy PRIMARY