title: Ultrafast Time-Resolved X-ray Absorption Spectroscopy of Ferrioxalate Photolysis with a Laser Plasma X-ray Source and Microcalorimeter Array.
abstract: The detailed pathways of photoactivity on ultrafast time scales are a topic of contemporary interest. Using a tabletop apparatus based on a laser plasma X-ray source and an array of cryogenic microcalorimeter X-ray detectors, we measured a transient X-ray absorption spectrum during the ferrioxalate photoreduction reaction. With these high-efficiency detectors, we observe the Fe K edge move to lower energies and the amplitude of the extended X-ray absorption fine structure reduce, consistent with a photoreduction mechanism in which electron transfer precedes disassociation. These results are compared to previously published transient X-ray absorption measurements on the same reaction and found to be consistent with the results from Ogi et al. and inconsistent with the results of Chen et al. ( Ogi , Y. ; et al. Struct. Dyn. 2015 , 2 , 034901 ; Chen , J. ; Zhang , H. ; Tomov , I. V. ; Ding , X. ; Rentzepis , P. M. Chem. Phys. Lett. 2007 , 437 , 50 - 55 ). We provide quantitative limits on the Fe-O bond length change. Finally, we review potential improvements to our measurement technique, highlighting the future potential of tabletop X-ray science using microcalorimeter sensors.
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Galen C
authors.identifier: http://orcid.org/0000-0003-3450-2263
authors.initials: GC
authors.lastname: O'Neil
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Luis
authors.initials: L
authors.lastname: Miaja-Avila
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Young Il
authors.initials: YI
authors.lastname: Joe
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Bradley K
authors.initials: BK
authors.lastname: Alpert
authors.affiliation: Advanced Photon Source, Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Mahalingam
authors.initials: M
authors.lastname: Balasubramanian
authors.affiliation: JILA, National Institute of Standards and Technology and University of Colorado Boulder , Boulder, Colorado 80309, United States.
authors.forename: D M
authors.initials: DM
authors.lastname: Sagar
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: William
authors.initials: W
authors.lastname: Doriese
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Fowler
authors.affiliation: Department of Chemical Physics, Lund University , Lund 223 62, Sweden.
authors.forename: Wilfred K
authors.initials: WK
authors.lastname: Fullagar
authors.affiliation: Canadian Light Source , Saskatoon, Saskatchewan S7N 2V3, Canada.
authors.forename: Ning
authors.initials: N
authors.lastname: Chen
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Gene C
authors.initials: GC
authors.lastname: Hilton
authors.affiliation: JILA, National Institute of Standards and Technology and University of Colorado Boulder , Boulder, Colorado 80309, United States.|Department of Chemistry and Biochemistry, University of Colorado Boulder , Boulder, Colorado 80309, United States.
authors.forename: Ralph
authors.identifier: http://orcid.org/0000-0002-8989-405X
authors.initials: R
authors.lastname: Jimenez
authors.affiliation: National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Bruce
authors.initials: B
authors.lastname: Ravel
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Carl D
authors.initials: CD
authors.lastname: Reintsema
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Dan R
authors.initials: DR
authors.lastname: Schmidt
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Silverman
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Swetz
authors.affiliation: Department of Chemical Physics, Lund University , Lund 223 62, Sweden.
authors.forename: Jens
authors.initials: J
authors.lastname: Uhlig
authors.affiliation: National Institute of Standards and Technology , Boulder, Colorado 80305, United States.|Department of Physics, University of Colorado Boulder , Boulder, Colorado 80309, United States.
authors.forename: Joel N
authors.initials: JN
authors.lastname: Ullom