Vibrational specificity and isotopic dependence of proton-transfer dynamics in electronically excited 6-hydroxy-2-formylfulvene

Foguel, Lidor

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https://hdl.handle.net/2142/104230 Copy

Description

Title

Vibrational specificity and isotopic dependence of proton-transfer dynamics in electronically excited 6-hydroxy-2-formylfulvene

Author(s)

Foguel, Lidor

Contributor(s)

• Vaccaro, Patrick
• Vealey, Zachary

Issue Date

2019-06-17

Keyword(s)

• Large amplitude motions
• Internal rotation

Abstract

The vibrational specificity and isotopic dependence of hindered proton-transfer dynamics have been explored in the lowest-lying singlet excited state, \textit{\~{A}}$^{1}$B$_{2}$ ($\pi$$^{*}$$\pi$), of 6-hydroxy-2-formylfulvene (HFF) and its monodeuterated isotopolog (HFF-\textit{d}). Both systems have been probed under bulk-gas conditions by employing polarization-resolved degenerate four-wave mixing (DFWM) spectroscopy, where judicious selection of incident and detected polarization geometries served to alleviate spectral complexity and to allow for the quantitative extraction of rotation-tunneling information. The observed $>$1000-fold decrease in tunneling rate that accompanies the $\pi$$^{*}$$\leftarrow$ $\pi$ electron promotion (transitioning from ultrafast ground-state dynamics\footnote{Z. N. Vealey, L. Foguel and P. H. Vaccaro, \textit{J. Phys. Chem. Lett.} \textbf{9}, 4949 (2018)} to near-complete quenching of analogous excited-state behavior) makes HFF a compelling model system for investigating the nuanced nature of low-barrier hydrogen bonding and its ability to regulate attendant hydron-migration events. A thorough analysis of low-energy vibronic bands in the \textit{\~{A}}$^{1}$B$_{2}$ manifold will be presented, with the dependence of unimolecular reactivity on heavy atom motion and isotopic modification being discussed in the context of structural predictions emerging from high-level quantum-chemical calculations.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/104230

DOI

https://doi.org/10.15278/isms.2019.MI09

Copyright and License Information

Copyright 2019 Lidor Foguel

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