Concerted Electron-Nuclear Motion in Proton-Coupled Electron Transfer-Driven Grotthuss-Type Proton Translocation
- Department of Chemistry, University of California, Berkeley, California 94720, United States, Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States, Kavli Energy Nanoscience Institute at Berkeley, Berkeley, California 94720, United States
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Department of Chemistry, University of California, Berkeley, California 94720, United States, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States, The Biodesign Institute Center for Applied Structural Discovery (CASD), Tempe, Arizona 85287, United States
Photoinduced proton-coupled electron transfer and long-range two-proton transport via a Grotthuss-type mechanism are investigated in a biomimetic construct. The ultrafast, nonequilibrium dynamics are assessed via two-dimensional electronic vibrational spectroscopy, in concert with electrochemical and computational techniques. A low- frequency mode is identified experimentally and found to promote double proton and electron transfer, supported by recent theoretical simulations of a similar but abbreviated (non-photoactive) system. Excitation frequency peak evolution and center line slope dynamics show direct evidence of strongly coupled nuclear and electronic degrees of freedom, from which we can conclude that the double proton and electron transfer processes are concerted (up to an uncertainty of 24 fs). The nonequilibrium pathway from the photoexcited Franck-Condon region to the E2PT state is characterized by an ~110 fs time scale. This study and the tools presented herein constitute a new window into hot charge transfer processes involving an electron and multiple protons.
- Research Organization:
- University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Arizona State Univ., Tempe, AZ (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; National Science Foundation (NSF); National Institutes of Health (NIH), National Institute of General Medical Sciences (NIGMS); Japan Society for the Promotion of Science (JSPS); USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Grant/Contract Number:
- FG02-03ER15393; SC0021186; DEAC02 05CH11231; AC02-05CH11231; DGE 1752814; F32GM142231
- OSTI ID:
- 1867899
- Alternate ID(s):
- OSTI ID: 1870112; OSTI ID: 1896690; OSTI ID: 1906923
- Journal Information:
- Journal of Physical Chemistry Letters, Journal Name: Journal of Physical Chemistry Letters Vol. 13 Journal Issue: 20; ISSN 1948-7185
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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