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Ogi Y, Obara Y, Katayama T, Suzuki YI, Liu SY, Bartlett NCM, Kurahashi N, Karashima S, Togashi T, Inubushi Y, Ogawa K, Owada S, Rubešová M, Yabashi M, Misawa K, Slavíček P, Suzuki T. Ultraviolet photochemical reaction of [Fe(III)(C2O4)3](3-) in aqueous solutions studied by femtosecond time-resolved X-ray absorption spectroscopy using an X-ray free electron laser. Struct Dyn 2015; 2:034901. [PMID: 26798796 PMCID: PMC4711623 DOI: 10.1063/1.4918803] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 04/28/2015] [Accepted: 04/13/2015] [Indexed: 05/06/2023]
Abstract
Time-resolved X-ray absorption spectroscopy was performed for aqueous ammonium iron(III) oxalate trihydrate solutions using an X-ray free electron laser and a synchronized ultraviolet laser. The spectral and time resolutions of the experiment were 1.3 eV and 200 fs, respectively. A femtosecond 268 nm pulse was employed to excite [Fe(III)(C2O4)3](3-) in solution from the high-spin ground electronic state to ligand-to-metal charge transfer state(s), and the subsequent dynamics were studied by observing the time-evolution of the X-ray absorption spectrum near the Fe K-edge. Upon 268 nm photoexcitation, the Fe K-edge underwent a red-shift by more than 4 eV within 140 fs; however, the magnitude of the redshift subsequently diminished within 3 ps. The Fe K-edge of the photoproduct remained lower in energy than that of [Fe(III)(C2O4)3](3-). The observed red-shift of the Fe K-edge and the spectral feature of the product indicate that Fe(III) is upon excitation immediately photoreduced to Fe(II), followed by ligand dissociation from Fe(II). Based on a comparison of the X-ray absorption spectra with density functional theory calculations, we propose that the dissociation proceeds in two steps, forming first [(CO2 (•))Fe(II)(C2O4)2](3-) and subsequently [Fe(II)(C2O4)2](2-).
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Affiliation(s)
- Y Ogi
- Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics , 2-1 Hirosawa, Wako 351-0198, Japan
| | | | - T Katayama
- Japan Synchrotron Radiation Research Institute , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Y-I Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - S Y Liu
- Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics , 2-1 Hirosawa, Wako 351-0198, Japan
| | - N C-M Bartlett
- Molecular Reaction Dynamics Research Team, RIKEN Center for Advanced Photonics , 2-1 Hirosawa, Wako 351-0198, Japan
| | - N Kurahashi
- Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - S Karashima
- Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - T Togashi
- Japan Synchrotron Radiation Research Institute , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Y Inubushi
- Japan Synchrotron Radiation Research Institute , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - K Ogawa
- RIKEN SPring-8 Center , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - S Owada
- RIKEN SPring-8 Center , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - M Rubešová
- Department of Physical Chemistry, University of Chemistry and Technology , Technická 5, Prague 6 16628, Czech Republic
| | - M Yabashi
- RIKEN SPring-8 Center , 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | | | - P Slavíček
- Department of Physical Chemistry, University of Chemistry and Technology , Technická 5, Prague 6 16628, Czech Republic
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Bartlett NCM, Jankunas J, Zare RN. False estimates of stimulated Raman pumping efficiency caused by the optical Stark effect. J Chem Phys 2011; 134:234310. [PMID: 21702559 DOI: 10.1063/1.3601923] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
One technique for measuring the fraction of molecules pumped to the excited state in stimulated Raman pumping (SRP) is to record the depletion of molecules in the lower state by resonance enhanced multiphoton ionization (REMPI). The presence of electric fields on the order of 10(7) V/cm arising from the pulsed SRP laser beams is sufficient to shift the line position of the REMPI transition to such an extent that the estimate of the pumping efficiency is overestimated unless this shift is accounted for.
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Affiliation(s)
- N C-M Bartlett
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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