title: Temporal mapping of photochemical reactions and molecular excited states with carbon specificity.
abstract: Photochemical reactions are essential to a large number of important industrial and biological processes. A method for monitoring photochemical reaction kinetics and the dynamics of molecular excitations with spatial resolution within the active molecule would allow a rigorous exploration of the pathway and mechanism of photophysical and photochemical processes. Here we demonstrate that laser-excited muon pump-probe spin spectroscopy (photo-μSR) can temporally and spatially map these processes with a spatial resolution at the single-carbon level in a molecule with a pentacene backbone. The observed time-dependent light-induced changes of an avoided level crossing resonance demonstrate that the photochemical reactivity of a specific carbon atom is modified as a result of the presence of the excited state wavefunction. This demonstrates the sensitivity and potential of this technique in probing molecular excitations and photochemistry.
authors.affiliation: College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China.|School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK.
authors.forename: K
authors.initials: K
authors.lastname: Wang
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK.
authors.forename: P
authors.initials: P
authors.lastname: Murahari
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK.|ISIS Muon Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
authors.forename: K
authors.initials: K
authors.lastname: Yokoyama
authors.affiliation: ISIS Muon Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
authors.forename: J S
authors.initials: JS
authors.lastname: Lord
authors.affiliation: ISIS Muon Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
authors.forename: F L
authors.initials: FL
authors.lastname: Pratt
authors.affiliation: College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: J
authors.initials: J
authors.lastname: He
authors.affiliation: College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: L
authors.initials: L
authors.lastname: Schulz
authors.affiliation: College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: M
authors.initials: M
authors.lastname: Willis
authors.affiliation: Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Anthony
authors.affiliation: Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK.
authors.forename: N A
authors.initials: NA
authors.lastname: Morley
authors.affiliation: University of Fribourg, Department of Physics and Fribourg Centre for Nanomaterials, Chemin du Museé 3, CH-1700 Fribourg, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Nuccio
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK.
authors.forename: A
authors.initials: A
authors.lastname: Misquitta
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Dunstan
authors.affiliation: Materials and Life Science Division, J-PARC Center, Tokai, Ibaraki 319-1195, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Shimomura
authors.affiliation: RIKEN-RAL, Nishina Centre, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Watanabe
authors.affiliation: College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS, UK.
authors.forename: P
authors.initials: P
authors.lastname: Heathcote
authors.affiliation: College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China.|School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK.|ISIS Muon Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Drew