University of Illinois Urbana-Champaign

UV DYNAMICS OF CIS-STILBENE STUDIED BY ULTRAFAST ELECTRON DIFFRACTION

Saha, S. K.

Content Files
6924.pdf
RH01_1.pdf
RH01_1.pptx

Permalink

https://hdl.handle.net/2142/122373

Description

Title
UV DYNAMICS OF CIS-STILBENE STUDIED BY ULTRAFAST ELECTRON DIFFRACTION
Author(s)
Saha, S. K.
Contributor(s)
  • Lin, Ming-Fu
  • Centurion, Martin
  • Martinez, Todd
  • Jobe, Keith
  • Yang, Jie
  • Wolf, Thomas JA
  • Pathak, Shashank
  • Ware, Matthew R
  • Ji, Fuhao
  • Hoffmann, Matthias
  • Luo, Duan
  • Moore, Bryan
  • Attar, Andrew
  • Williams, Monika
  • Weir, Hayley
  • Nunes, Pedr
Issue Date
2023-06-22
Keyword(s)
Photodissociation and photochemistry
Abstract
Stilbene is a prototype molecule for studying photoisomerization and photocyclization mechanisms which are pivotal to converting light into chemical and mechanical energy in nature. Despite multiple decades of research, the exact details of the photoisomerization of cis-stilbene into trans-stilbene and/or its cyclization into 4a,4b-dihydrophenanthrene (DHP) have remained a topic of debate. We have used mega-electronvolt ultrafast electron diffraction (UED) to capture and spatially resolve the photoexcitation dynamics with sub-angstrom resolution. At the SLAC MeV-UED beamline, cis-stilbene was optically pumped with 267 nm ultraviolet light with different pulse energy and probed with 3.7 MeV electrons. We compare our experimental difference-diffraction signals with Ab initio multiple spawning simulations (AIMS) for single-photon excitation dynamics and molecular dynamics simulation for two-photon excitation leading to ionization. We found that with 80uJ pulse energy, the single and two-photon excitation channels are comparable, while with 130uJ pulse energy the two-photon channel dominates. Our data and simulations revealed very different dynamics and end products in the one-photon and two-photon channels.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
Text
Genre of Resource
Conference Paper / Presentation
Language
eng
Handle URL
https://hdl.handle.net/2142/122373
DOI
https://doi.org/10.15278/isms.2023.6924

Owning Collections

Abstracts & Presentations - 2023 International Symposium on Molecular Spectroscopy PRIMARY