title: Anion resonances and above-threshold dynamics of coenzyme Q0.
abstract: Temporary radical anions (resonances) of isolated co enzyme Q0 (CQ0) and their associated above-threshold dynamics have been studied using frequency-, angle-, and time-resolved photoelectron imaging (FAT-PI). Experimental energetics and dynamics are supported with ab initio calculations. All results support that CQ0 exhibits similar resonances and energetics compared with the smaller para-benzoquinone subunit, which is commonly considered as a prototype electrophore for larger biological para-quinone species. However, the above-threshold dynamics in CQ0 relative to para-benzoquinone show significantly enhanced prompt detachment compared with internal conversion, particularly around the photoexcitation energy of 3.10 eV. The change in dynamics can be attributed to a combination of an increase in the shape character of the optically-accessible resonance at this energy, a decrease in the autodetachment lifetime due to the higher density of states in the neutral, and a decrease in the probability that the wavepacket formed in the Franck-Condon window can access the local conical intersection in CQ0 over the timescale of autodetachment. Overall, this study serves as a clear example in understanding the trends in spectroscopy and dynamics in relating a simple prototypical para-quinone electrophore to a more complex biochemical species.
authors.affiliation: Department of Chemistry, Durham University, South Road, DH1 3LE, UK. j.r.r.verlet@durham.ac.uk.
authors.forename: James N
authors.initials: JN
authors.lastname: Bull
authors.forename: Christopher W
authors.initials: CW
authors.lastname: West
authors.forename: Jan R R
authors.initials: JR
authors.lastname: Verlet
mesh_terms: D000838:Anions / Q000737:chemistry; D016227:Benzoquinones / Q000737:chemistry*; D004579:Electron Transport; D056951:Photoelectron Spectroscopy; D013997:Time Factors
chemical_list: D000838:Anions; D016227:Benzoquinones; C109863:ubiquinone-O