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Title:VIBRATIONAL SPECIFICITY OF PROTON-TRANSFER DYNAMICS IN ELECTRONICALLY EXCITED 6-HYDROXY-2-FORMYLFULVENE
Author(s):Foguel, Lidor
Contributor(s):Vaccaro, Patrick ; Vealey, Zachary
Subject(s):Comparing theory and experiment
Abstract:The transduction of protons between distinct donor and acceptor sites, as often directed by attendant hydrogen bonds, is a ubiquitous chemical transformation essential for all of acid/base chemistry, yet the role of selective nuclear displacements in this deceptively simple process remains a topic of active investigation. Polarization-resolved degenerate four-wave mixing (DFWM) spectroscopy was employed to investigate the vibrational specificity of proton-transfer dynamics in the lowest-lying singlet excited state, \textit{\~{A}}$^{1}$B$_{2}$ ($\pi$$^{*}$$\pi$), of 6-hydroxy-2-formylfulvene (HFF), with judicious selection of incident and detected polarization geometries allowing for the quantitative extraction of refined rotation-tunneling parameters. While the zero-point level of the ground electronic state [\textit{\~{X}}$^{1}$A$_{1}$] straddles the barrier crest for hydron migration and thus affords a prototypical example of low-barrier hydrogen bonding,\footnote{Z. N. Vealey, L. Foguel and P. H. Vaccaro, \textit{J. Phys. Chem. Lett.} \textbf{9}, 4949 (2018).} this model system also has been found to undergo a dramatic change in dynamics upon $\pi$$^{*}$$\leftarrow$ $\pi$ electron promotion – as reflected by a $>$1000-fold decrease in tunneling rates.\footnote{Z. N. Vealey, L. Foguel and P. H. Vaccaro, \textit{J. Phys. Chem. A.} \textbf{123}, 6506 (2019).} This talk will present complementary experimental and computational analyses of vibronic levels in the pertinent \textit{\~{A}}$^{1}$B$_{2}$ ($\pi$$^{*}$$\pi$) manifold designed to unravel the dependence of unimolecular reactivity on heavy atom motion and to elucidate the disparate behavior observed for analogous \textit{\~{X}}$^{1}$A$_{1}$ features.
Issue Date:24-Jun-20
Publisher:International Symposium on Molecular Spectroscopy
Citation Info:APS
Genre:CONFERENCE PAPER/PRESENTATION
Type:Text
Language:English
URI:http://hdl.handle.net/2142/107704
Date Available in IDEALS:2020-06-26


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