1
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Lamas I, González J, Longarte A, Montero R. Influence of H-bonds on the photoionization of aromatic chromophores in water: The aniline molecule. J Chem Phys 2023; 158:2890456. [PMID: 37184001 DOI: 10.1063/5.0147503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/01/2023] [Indexed: 05/16/2023] Open
Abstract
We have conducted time-resolved experiments (pump-probe and pump-repump-probe) on a model aromatic chromophore, aniline, after excitation in water at 267 nm. In the initial spectra recorded, in addition to the absorption corresponding to the bright ππ* excitation, the fingerprint of a transient state with the electron located on the solvent molecule is identified. We postulate that the latter corresponds to the πσ* state along the N-H bond, whose complete relaxation with a ∼500 ps lifetime results in the formation of the fully solvated electron and cation. This ionization process occurs in parallel with the ππ* photophysical channel that yields the characteristic ∼1 ns fluorescence lifetime. The observed branched pathway is rationalized in terms of the different H-bonds that the water establishes with the amino group. The proposed mechanism could be common for aromatics in water containing N-H or O-H bonds and would allow the formation of separated charges after excitation at the threshold of their electronic absorptions.
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Affiliation(s)
- Iker Lamas
- Facultad de Ciencia y Tecnología, Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain
| | - Jorge González
- Facultad de Ciencia y Tecnología, Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain
| | - Asier Longarte
- Facultad de Ciencia y Tecnología, Departamento de Química Física, Universidad del País Vasco (UPV/EHU), Apart. 644, 48080 Bilbao, Spain
| | - Raúl Montero
- Facultad de Ciencia y Tecnología, SGIKER Laser Facility, UPV/EHU, Sarriena, S/N, 48940 Leioa, Spain
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2
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Solti D, Chapkin KD, Renard D, Bayles A, Clark BD, Wu G, Zhou J, Tsai AL, Kürti L, Nordlander P, Halas NJ. Plasmon-Generated Solvated Electrons for Chemical Transformations. J Am Chem Soc 2022; 144:20183-20189. [DOI: 10.1021/jacs.2c07768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David Solti
- Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Kyle D. Chapkin
- Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
- Applied Physics Graduate Program, Smalley-Curl Institute, Rice University, Houston, Texas 77005, United States
| | - David Renard
- Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Aaron Bayles
- Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Benjamin D. Clark
- Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Gang Wu
- Department of Internal Medicine, The University of Texas McGovern Medical School, Houston, Texas 77030, United States
| | - Jingyi Zhou
- Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States
- Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States
| | - Ah-Lim Tsai
- Department of Internal Medicine, The University of Texas McGovern Medical School, Houston, Texas 77030, United States
| | - László Kürti
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Peter Nordlander
- Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
- Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Naomi J. Halas
- Laboratory for Nanophotonics, Rice University, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, United States
- Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
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3
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Cook AR. Sub-picosecond Production of Solute Radical Cations in Tetrahydrofuran after Radiolysis. J Phys Chem A 2021; 125:10189-10197. [PMID: 34793148 DOI: 10.1021/acs.jpca.1c08568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ultrafast hole transfer from solvent radical cations produced by radiolysis with ∼10 ps, 9 MeV electron pulses to solutes in tetrahydrofuran (THF) was investigated. Because of rapid fragmentation of initially produced THF+•, solute radical cations are not expected and have not previously been reported. When 9,9-dihexyl-2,7-dibromofluorene (Br2F) at 5 to 1000 mM was used, Br2F+• with radiation chemical yields up to G = 2.23/100 eV absorbed was observed. While more than half of this was the result of direct solute ionization, the results highlight the importance of capturing holes from THF+• prior to solvation and fragmentation. The observed data show a time-resolution limited (15 ps) rise in transient absorption of Br2F+•, identical in form to reports of presolvated or dry electron capture in water and a few organic liquids, including THF. The results were thus interpreted with a similar formalism, finding C37 = 1.7 M, the concentration at which 37% of holes escape capture. The yield of solvent hole capture can be accounted for by the formation of solvent holes adjacent to solute molecules reacting faster than they can fragment; however, mechanisms such as delocalized holes or rapid hopping may play a role. Low temperature results find over two times more capture, supporting the speculation that if THF+• was longer lived, the yield of capture in under 15 ps would have been at least 2 times larger at 1 M Br2F, possibly capturing nearly all available holes from the solvent.
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Affiliation(s)
- Andrew R Cook
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, United States
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4
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Beregovaya IV, Tretyakova IS, Borovkov VI. An Updated View of Primary Ionization Processes in Polar Liquids. J Phys Chem Lett 2021; 12:11573-11577. [PMID: 34807617 DOI: 10.1021/acs.jpclett.1c03388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
According to picosecond radiolysis data, primary radical cations in irradiated carbonates are very rapidly deprotonated. At the same time, analysis of the radiation-induced fluorescence from carbonate solutions indicates the formation of solvent-related radical cationic species with a relatively long lifetime. We use quantum chemical methods to develop a model of carbonate ionization that reconciles these conflicting data. Using ethylene carbonate as an example and assuming that its molecules exist in solution as a collection of dimeric associates, we show that both processes are the result of the loss of an electron from such dimers. This demonstrates that the generally accepted conceptualization of a primary ionization event, based on the idea of the formation of a radical cation of an individual molecule of an irradiated substance, requires revision in the case of polar aprotic liquids that tend to form molecular associates.
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Affiliation(s)
- Irina V Beregovaya
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of Russian Academy of Science, 9 Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Irina S Tretyakova
- Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Science, 3 Institutskaya st., Novosibirsk 630090, Russia
| | - Vsevolod I Borovkov
- Voevodsky Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Science, 3 Institutskaya st., Novosibirsk 630090, Russia
- Novosibirsk State University, 2 Pirogova st., Novosibirsk 630090, Russia
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5
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Jayasekara GK, Antolini C, Smith MA, Jacoby DJ, Escolastico J, Girard N, Young BT, Hayes D. Mechanisms of the Cu(I)-Catalyzed Intermolecular Photocycloaddition Reaction Revealed by Optical and X-ray Transient Absorption Spectroscopies. J Am Chem Soc 2021; 143:19356-19364. [PMID: 34752703 DOI: 10.1021/jacs.1c07282] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The [2 + 2] photocycloaddition provides a simple, single-step route to cyclobutane moieties that would otherwise be disfavored or impossible due to ring strain and/or steric interactions. We have used a combination of optical and X-ray transient absorption spectroscopies to elucidate the mechanism of the Cu(I)-catalyzed intermolecular photocycloaddition reaction using norbornene and cyclohexene as model substrates. We find that for norbornene the reaction proceeds through an initial metal-to-ligand charge transfer (MLCT) state that persists for 18 ns before the metal returns to the monovalent oxidation state. The Cu K-edge spectrum continues to evolve until ∼5 μs and then remains unchanged for the 50 μs duration of the measurement, reflecting product formation and ligand dissociation. We hypothesize that the MLCT transition and reverse electron transfer serve to sensitize the triplet excited state of one of the norbornene ligands, which then dimerizes with the other to give the product. For the case of cyclohexene, however, we do not observe a charge transfer state following photoexcitation and instead find evidence for an increase in the metal-ligand bond strength that persists for several ns before product formation occurs. This is consistent with a mechanism in which ligand photoisomerization is the initial step, which was first proposed by Salomon and Kochi in 1974 to explain the stereoselectivity of the reaction. Our investigation reveals how this photocatalytic reaction may be directed along strikingly disparate trajectories by only very minor changes to the structure of the substrate.
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Affiliation(s)
- Gethmini K Jayasekara
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Cali Antolini
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Melissa A Smith
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Danielle J Jacoby
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Jacqueline Escolastico
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Nathan Girard
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Benjamin T Young
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Dugan Hayes
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
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6
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Photoexcitation of Ge 9- Clusters in THF: New Insights into the Ultrafast Relaxation Dynamics and the Influence of the Cation. Molecules 2020; 25:molecules25112639. [PMID: 32517154 PMCID: PMC7321105 DOI: 10.3390/molecules25112639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/15/2020] [Accepted: 06/03/2020] [Indexed: 11/18/2022] Open
Abstract
We present a comprehensive femtosecond (fs) transient absorption study of the [Ge9(Hyp)3]− (Hyp = Si(SiMe3)3) cluster solvated in tetrahydrofuran (THF) with special emphasis on intra- and intermolecular charge transfer mechanisms which can be tuned by exchange of the counterion and by dimerization of the cluster. The examination of the visible and the near infrared (NIR) spectral range reveals four different processes of cluster dynamics after UV (267/258 nm) photoexcitation related to charge transfer to solvent and localized excited states in the cluster. The resulting transient absorption is mainly observed in the NIR region. In the UV-Vis range transient absorption of the (neutral) cluster core with similar dynamics can be observed. By transferring concepts of: (i) charge transfer to the solvent known from solvated Na− in THF and (ii) charge transfer in bulk-like materials on metalloid cluster systems containing [Ge9(Hyp)3]− moieties, we can nicely interpret the experimental findings for the different compounds. The first process occurs on a fs timescale and is attributed to localization of the excited electron in the quasi-conduction band/excited state which competes with a charge transfer to the solvent. The latter leads to an excess electron initially located in the vicinity of the parent cluster within the same solvent shell. In a second step, it can recombine with the cluster core with time constants in the picosecond (ps) timescale. Some electrons can escape the influence of the cluster leading to a solvated electron or after interaction with a cation to a contact pair both with lifetimes exceeding our experimentally accessible time window of 1 nanosecond (ns). An additional time constant on a tens of ps timescale is pronounced in the UV-Vis range which can be attributed to the recombination rate of the excited state or quasi conduction band of Ge9−. In the dimer, the excess electron cannot escape the molecule due to strong trapping by the Zn cation that links the two cluster cores.
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7
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Pavliuk MV, Gutiérrez Álvarez S, Hattori Y, Messing ME, Czapla-Masztafiak J, Szlachetko J, Silva JL, Araujo CM, A Fernandes DL, Lu L, Kiely CJ, Abdellah M, Nordlander P, Sá J. Hydrated Electron Generation by Excitation of Copper Localized Surface Plasmon Resonance. J Phys Chem Lett 2019; 10:1743-1749. [PMID: 30920838 DOI: 10.1021/acs.jpclett.9b00792] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Hydrated electrons are important in radiation chemistry and charge-transfer reactions, with applications that include chemical damage of DNA, catalysis, and signaling. Conventionally, hydrated electrons are produced by pulsed radiolysis, sonolysis, two-ultraviolet-photon laser excitation of liquid water, or photodetachment of suitable electron donors. Here we report a method for the generation of hydrated electrons via single-visible-photon excitation of localized surface plasmon resonances (LSPRs) of supported sub-3 nm copper nanoparticles in contact with water. Only excitations at the LSPR maximum resulted in the formation of hydrated electrons, suggesting that plasmon excitation plays a crucial role in promoting electron transfer from the nanoparticle into the solution. The reactivity of the hydrated electrons was confirmed via proton reduction and concomitant H2 evolution in the presence of a Ru/TiO2 catalyst.
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Affiliation(s)
- Mariia V Pavliuk
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
| | - Sol Gutiérrez Álvarez
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
| | - Yocefu Hattori
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
| | - Maria E Messing
- Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
| | | | - Jakub Szlachetko
- Institute of Nuclear Physics , Polish Academy of Sciences , PL-31342 Krakow , Poland
- Institute of Physical Chemistry , Polish Academy of Sciences , 01-224 Warsaw , Poland
| | - Jose L Silva
- Materials Theory Division, Department of Physics and Astronomy , Uppsala University , 75120 Uppsala , Sweden
| | - Carlos Moyses Araujo
- Materials Theory Division, Department of Physics and Astronomy , Uppsala University , 75120 Uppsala , Sweden
| | - Daniel L A Fernandes
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
| | - Li Lu
- Department of Materials Science and Engineering , Lehigh University , 5 East Packer Avenue , Bethlehem , Pennsylvania 18015 , United States
| | - Christopher J Kiely
- Department of Materials Science and Engineering , Lehigh University , 5 East Packer Avenue , Bethlehem , Pennsylvania 18015 , United States
| | - Mohamed Abdellah
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
- Department of Chemistry, Qena Faculty of Science , South Valley University , 83523 Qena , Egypt
| | - Peter Nordlander
- Department of Physics , Rice University , 6100 South Main Street , Houston , Texas 77251-1892 , United States
| | - Jacinto Sá
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
- Institute of Physical Chemistry , Polish Academy of Sciences , 01-224 Warsaw , Poland
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8
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Chen HC, Cook AR, Asaoka S, Boschen JS, Windus TL, Miller JR. Escape of anions from geminate recombination in THF due to charge delocalization. Phys Chem Chem Phys 2018; 19:32272-32285. [PMID: 29192921 DOI: 10.1039/c7cp05880b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Geminate recombination of 24 radical anions (M˙-) with solvated protons (RH2+) was studied in tetrahydrofuran (THF) with pulse radiolysis. The recombination has two steps: (1) diffusion of M˙- and RH2+ together to form intimate (contact and solvent separated) ion pairs, driven by Coulomb attraction; (2) annihilation of anions due to proton transfer (PT) from RH2+ to M˙-. The non-exponential time-dependence of the geminate diffusion was determined. For all molecules protonated on O or N atoms the subsequent PT step is too fast (<0.2 ns) to measure, except for the anion of TCNE which did not undergo proton transfer. PT to C atoms was as slow as 70 ns and was always slow enough to be observable. A possible effect of charge delocalization on the PT rates could not be clearly separated from other factors. For 21 of the 24 molecules studied here, a free ion yield (71.6 ± 6.2 nmol J-1) comprising ∼29% of the total, was formed. This yield of "Type I" free ions is independent of the PT rate because it arises entirely by escape from the initial distribution of ion pair distances without forming intimate ion pairs. Three anions of oligo(9,9-dihexyl)fluorenes, Fn˙- (n = 2-4) were able to escape from intimate ion-pairs to form additional yields of "Type II" free ions with escape rate constants near 3 × 106 s-1. These experiments find no evidence for an inverted region for proton transfer.
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Affiliation(s)
- Hung-Cheng Chen
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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9
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Cook AR, Valášek M, Funston AM, Poliakov P, Michl J, Miller JR. p-Carborane Conjugation in Radical Anions of Cage–Cage and Cage–Phenyl Compounds. J Phys Chem A 2018; 122:798-810. [DOI: 10.1021/acs.jpca.7b10885] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew R. Cook
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Michal Valášek
- Institute
of Organic Chemistry and Biochemistry, ASCR, Prague 6 16610, Czech Republic
| | - Alison M. Funston
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
- School
of Chemistry, Monash University, Clayton, Victoria 3800, Australia
| | - Pavel Poliakov
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Josef Michl
- Institute
of Organic Chemistry and Biochemistry, ASCR, Prague 6 16610, Czech Republic
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - John R. Miller
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
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10
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Wang F, Varenne F, Ortiz D, Pinzio V, Mostafavi M, Le Caër S. Degradation of an Ethylene Carbonate/Diethyl Carbonate Mixture by Using Ionizing Radiation. Chemphyschem 2017; 18:2799-2806. [DOI: 10.1002/cphc.201700320] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Furong Wang
- Laboratoire de Chimie-Physique/ELYSE, UMR 8000 CNRS/UPSUniversité Paris Sud, Bât. 349 F-91405 Orsay Cedex France
| | - Fanny Varenne
- LIONS, NIMBE, UMR 3685, CEA, CNRSUniversité Paris-Saclay, CEA Saclay, Bât. 546 F-91191 Gif-sur-Yvette Cedex France
| | - Daniel Ortiz
- LIONS, NIMBE, UMR 3685, CEA, CNRSUniversité Paris-Saclay, CEA Saclay, Bât. 546 F-91191 Gif-sur-Yvette Cedex France
| | - Valentin Pinzio
- LIONS, NIMBE, UMR 3685, CEA, CNRSUniversité Paris-Saclay, CEA Saclay, Bât. 546 F-91191 Gif-sur-Yvette Cedex France
| | - Mehran Mostafavi
- Laboratoire de Chimie-Physique/ELYSE, UMR 8000 CNRS/UPSUniversité Paris Sud, Bât. 349 F-91405 Orsay Cedex France
| | - Sophie Le Caër
- LIONS, NIMBE, UMR 3685, CEA, CNRSUniversité Paris-Saclay, CEA Saclay, Bât. 546 F-91191 Gif-sur-Yvette Cedex France
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11
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Affiliation(s)
- John M. Herbert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Marc P. Coons
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
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12
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Yasui S, Kobayashi S, Mishima M. Comprehensive investigation on the reactivity of triarylphosphine radical cations by laser flash photolysis time-resolved UV-Vis spectroscopy. J PHYS ORG CHEM 2016. [DOI: 10.1002/poc.3557] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Shinro Yasui
- Institute of Human and Environmental Sciences; Tezukayama University; Gakuen-Minami Nara 631-8585 Japan
| | - Shinjiro Kobayashi
- Institute for Materials Chemistry and Engineering; Kyushu University; 744 Motooka, Nishi-ku Fukuoka 819-0395 Japan
| | - Masaaki Mishima
- Institute for Materials Chemistry and Engineering; Kyushu University; 744 Motooka, Nishi-ku Fukuoka 819-0395 Japan
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13
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Yasui S, Ogawa Y, Shioji K, Mishima M, Yamazaki S. Dramatic Effect of Atmosphere on Product Distribution from Steady-State Photolysis of Triarylphosphines. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2014. [DOI: 10.1246/bcsj.20140100] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Shinro Yasui
- Faculty of Contemporary Human Life Science, Tezukayama University
| | - Yuya Ogawa
- Department of Chemistry, Faculty of Science, Fukuoka University
| | - Kosei Shioji
- Department of Chemistry, Faculty of Science, Fukuoka University
| | - Masaaki Mishima
- Institute for Materials Chemistry and Engineering, Kyushu University
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14
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Taletskiy KS, Borovkov VI, Shchegoleva LN, Beregovaya IV, Bagryansky VA, Molin YN. Unusual transformation of primary radical cations in irradiated liquid tetrahydrofuran. DOKLADY PHYSICAL CHEMISTRY 2014. [DOI: 10.1134/s0012501614030026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Borovkov VI, Ivanishko IS. Measurement of the Relative Mobility of Geminate Ions in Ethereal Solutions of Aromatic Compounds Using the Fluorescence Response of the Solutions to Pulsed Irradiation. J Phys Chem B 2013; 117:15122-30. [DOI: 10.1021/jp4093942] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- V. I. Borovkov
- Institute of Chemical Kinetics and Combustion, SB RAS, Novosibirsk, Institutskaya St., 3, 630090, Russia
- Novosibirsk State University, Novosibirsk, Pirogova St., 2, 630090, Russia
| | - I. S. Ivanishko
- Institute of Chemical Kinetics and Combustion, SB RAS, Novosibirsk, Institutskaya St., 3, 630090, Russia
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16
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Schmierer T, Ryseck G, Villnow T, Regner N, Gilch P. Kasha or state selective behavior in the photochemistry of ortho-nitrobenzaldehyde? Photochem Photobiol Sci 2012; 11:1313-21. [DOI: 10.1039/c2pp25057h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Cook AR, Sreearunothai P, Asaoka S, Miller JR. Sudden, “Step” Electron Capture by Conjugated Polymers. J Phys Chem A 2011; 115:11615-23. [DOI: 10.1021/jp205790k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrew R. Cook
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793-5000
| | - Paiboon Sreearunothai
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793-5000
- Sirindhorn International Institute of Technology, Thammasat University, Pathum Thai 12121, Thailand
| | - Sadayuki Asaoka
- Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, 226-8503, Japan
| | - John R. Miller
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793-5000
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18
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Glover WJ, Larsen RE, Schwartz BJ. Simulating the formation of sodium:electron tight-contact pairs: watching the solvation of atoms in liquids one molecule at a time. J Phys Chem A 2011; 115:5887-94. [PMID: 21428430 DOI: 10.1021/jp1101434] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The motions of solvent molecules during a chemical transformation often dictate both the dynamics and the outcome of solution-phase reactions. However, a microscopic picture of solvation dynamics is often obscured by the concerted motions of numerous solvent molecules that make up a condensed-phase environment. In this study, we use mixed quantum/classical molecular dynamics simulations to furnish the molecular details of the solvation dynamics that leads to the formation of a sodium cation-solvated electron contact pair, (Na(+), e(-)), in liquid tetrahydrofuran following electron photodetachment from sodide (Na(-)). Our simulations reveal that the dominant solvent response is comprised of a series of discrete solvent molecular events that work sequentially to build up a shell of coordinating THF oxygen sites around the sodium cation end of the contact pair. With the solvent response described in terms of the sequential motion of single molecules, we are then able to compare the calculated transient absorption spectroscopy of the sodium species to experiment, providing a clear microscopic interpretation of ultrafast pump-probe experiments on this system. Our findings suggest that for solute-solvent interactions similar to the ones present in our study, the solvation dynamics is best understood as a series of kinetic events consisting of reactions between chemically distinct local structures in which key solvent molecules must be considered to be part of the identity of the reacting species.
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Affiliation(s)
- William J Glover
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
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Glover WJ, Larsen RE, Schwartz BJ. First principles multielectron mixed quantum/classical simulations in the condensed phase. I. An efficient Fourier-grid method for solving the many-electron problem. J Chem Phys 2010; 132:144101. [DOI: 10.1063/1.3352564] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Glover WJ, Larsen RE, Schwartz BJ. First principles multielectron mixed quantum/classical simulations in the condensed phase. II. The charge-transfer-to-solvent states of sodium anions in liquid tetrahydrofuran. J Chem Phys 2010; 132:144102. [DOI: 10.1063/1.3352565] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Larsen MC, Schwartz BJ. Searching for solvent cavities via electron photodetachment: The ultrafast charge-transfer-to-solvent dynamics of sodide in a series of ether solvents. J Chem Phys 2009; 131:154506. [DOI: 10.1063/1.3245864] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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22
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Sreearunothai P, Asaoka S, Cook AR, Miller JR. Length and Time-Dependent Rates in Diffusion-Controlled Reactions with Conjugated Polymers. J Phys Chem A 2009; 113:2786-95. [DOI: 10.1021/jp809413x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paiboon Sreearunothai
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793–5000 and Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, 226–8503, Japan
| | - Sadayuki Asaoka
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793–5000 and Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, 226–8503, Japan
| | - Andrew R. Cook
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793–5000 and Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, 226–8503, Japan
| | - John R. Miller
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793–5000 and Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, 226–8503, Japan
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Abstract
The dynamics of short-lived charges generated by pulsed radiations such as electron beam (EB) and photon was investigated to elucidate their reactivity, electronic properties, and spatial behavior on a nanometer scale. Chemical reactions of radical cations (hole) and anions (electron) in condensed matter (organic liquids, polymers, and conjugated materials) occupy an important place in postoptical nanolithography and organic electric devices. The spatiotemporal evolution of charges during geminate ion recombination was measured by a highly improved picosecond (ps) pulse radiolysis and incorporated into a Monte Carlo simulation to clarify the key role of the charges in the formation of latent image roughness of chemically amplified resists (CARs). The dynamics and alternating-current (AC) mobility of transient charge carriers in conjugated materials such as polymer and organic crystals were studied by the combination of microwave conductivity and optical spectroscopies, revealing the potential plausibility for high-performance electric devices. Anisotropy measurement and methodology to resolve the sum of mobility into hole and electron components without electrodes have also been demonstrated.
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Glover WJ, Larsen RE, Schwartz BJ. The roles of electronic exchange and correlation in charge-transfer-to-solvent dynamics: Many-electron nonadiabatic mixed quantum/classical simulations of photoexcited sodium anions in the condensed phase. J Chem Phys 2008; 129:164505. [DOI: 10.1063/1.2996350] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Cavanagh MC, Young RM, Schwartz BJ. The roles of the solute and solvent cavities in charge-transfer-to-solvent dynamics: Ultrafast studies of potasside and sodide in diethyl ether. J Chem Phys 2008; 129:134503. [DOI: 10.1063/1.2977995] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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27
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Asaoka S, Takeda N, Iyoda T, Cook AR, Miller JR. Electron and hole transport to trap groups at the ends of conjugated polyfluorenes. J Am Chem Soc 2008; 130:11912-20. [PMID: 18698770 DOI: 10.1021/ja800426z] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polyfluorenes (pF) were synthesized having anthraquinone (AQ) or naphtylimide (NI) end caps that trap electrons or di- p-tolylaminophenyl (APT2) caps that trap holes. The average lengths of the pF chains in these molecules varied from 7 to 30 nm. End capping was found not to be complete in these molecules so that some were without caps. Electrons or holes were injected into these polymers in solution by pulse radiolysis. Following attachment, the charges migrated to the end cap traps in times near 2 ns in pF12AQ or 5 ns in pF35NI. From these observations, electron mobilities for transport along single chains to the end caps in THF solution were determined to be smaller by a factor of 100 than those observed by microwave conductivity. Despite this, the mobilities were sufficiently large to provide encouragement to the use of such single chains in solar photovoltaics. Most charges were observed to transport over substantial distances in these polymers, but 23, 18, and 37% of the charges attached to pFNI, pFAQ, and pFAPT2, respectively, were trapped in the pF chains and decayed by slower bimolecular reactions. For pFAQ and pFAPT2, all of the trapped charges were accounted for by estimates of the fraction of molecules having no end cap traps. For pF35NI, 23% of the attached electrons were found to be trapped in the chains, but only 4% of chains were expected to have no end caps. This could indicate some trapping by kinks or other defects but may just reflect uncertainties in the capping of this long polymer. When the charges reach the trap groups, their spectra have no features of pF(*-) or pF(*+), nor do the principal bands of the trapped ions resemble spectra of the radical ions of isolated trap molecules. The optical absorption spectra are rather dominated by new bands identified as charge-transfer transitions, which probably reinject electrons or holes into the pF chains. The energies of those bands correlate well with measured redox potentials.
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Affiliation(s)
- Sadayuki Asaoka
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
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Shoshanim O, Ruhman S. Na− photolysis in THF: Charge transfer to solvent studied from the donors perspective in <10fs detail. J Chem Phys 2008; 129:044502. [DOI: 10.1063/1.2946701] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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29
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Affiliation(s)
- Xiyi Chen
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482;
| | - Stephen E. Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482;
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Bragg AE, Schwartz BJ. Ultrafast Charge-Transfer-to-Solvent Dynamics of Iodide in Tetrahydrofuran. 2. Photoinduced Electron Transfer to Counterions in Solution. J Phys Chem A 2008; 112:3530-43. [DOI: 10.1021/jp712039u] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arthur E. Bragg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569
| | - Benjamin J. Schwartz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569
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Bragg AE, Schwartz BJ. The ultrafast charge-transfer-to-solvent dynamics of iodide in tetrahydrofuran. 1. Exploring the roles of solvent and solute electronic structure in condensed-phase charge-transfer reactions. J Phys Chem B 2007; 112:483-94. [PMID: 18085770 DOI: 10.1021/jp076934s] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although they represent the simplest possible charge-transfer reactions, the charge-transfer-to-solvent (CTTS) dynamics of atomic anions exhibit considerable complexity. For example, the CTTS dynamics of iodide in water are very different from those of sodide (Na-) in tetrahydrofuran (THF), leading to the question of the relative importance of the solvent and solute electronic structures in controlling charge-transfer dynamics. In this work, we address this issue by investigating the CTTS spectroscopy and dynamics of I- in THF, allowing us to make detailed comparisons to the previously studied I-/H2O and Na-/THF CTTS systems. Since THF is weakly polar, ion pairing with the counterion can have a substantial impact on the CTTS spectroscopy and dynamics of I- in this solvent. In this study, we have isolated "counterion-free" I- in THF by complexing the Na+ counterion with 18-crown-6 ether. Ultrafast pump-probe experiments reveal that THF-solvated electrons (e-THF) appear 380 +/- 60 fs following the CTTS excitation of "free" I- in THF. The absorption kinetics are identical at all probe wavelengths, indicating that the ejected electrons appear with no significant dynamic solvation but rather with their equilibrium absorption spectrum. After their initial appearance, ejected electrons do not exhibit any additional dynamics on time scales up to approximately 1 ns, indicating that geminate recombination of e-THF with its iodine atom partner does not occur. Competitive electron scavenging measurements demonstrate that the CTTS excited state of I- in THF is quite large and has contact with scavengers that are several nanometers away from the iodide ion. The ejection time and lack of electron solvation observed for I- in THF are similar to what is observed following CTTS excitation of Na- in THF. However, the relatively slow ejection time, the complete lack of dynamic solvation, and the large ejection distance/lack of recombination dynamics are in marked contrast to the CTTS dynamics observed for I- in water, in which fast electron ejection, substantial solvation, and appreciable recombination have been observed. These differences in dynamical behavior can be understood in terms of the presence of preexisting, electropositive cavities in liquid THF that are a natural part of its liquid structure; these cavities provide a mechanism for excited electrons to relocate to places in the liquid that can be nanometers away, explaining the large ejection distance and lack of recombination following the CTTS excitation of I- in THF. We argue that the lack of dynamic solvation observed following CTTS excitation of both I- and Na- in THF is a direct consequence of the fact that little additional relaxation is required once an excited electron nonadiabatically relaxes into one of the preexisting cavities. In contrast, liquid water contains no such cavities, and CTTS excitation of I- in water leads to local electron ejection that involves substantial solvent reorganization.
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Affiliation(s)
- Arthur E Bragg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
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Cavanagh MC, Larsen RE, Schwartz BJ. Watching Na Atoms Solvate into (Na+,e-) Contact Pairs: Untangling the Ultrafast Charge-Transfer-to-Solvent Dynamics of Na- in Tetrahydrofuran (THF). J Phys Chem A 2007; 111:5144-57. [PMID: 17523607 DOI: 10.1021/jp071132i] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
With the large dye molecules employed in typical studies of solvation dynamics, it is often difficult to separate the intramolecular relaxation of the dye from the relaxation associated with dynamic solvation. One way to avoid this difficulty is to study solvation dynamics using an atom as the solvation probe; because atoms have only electronic degrees of freedom, all of the observed spectroscopic dynamics must result from motions of the solvent. In this paper, we use ultrafast transient absorption spectroscopy to investigate the solvation dynamics of newly created sodium atoms that are formed following the charge transfer to solvent (CTTS) ejection of an electron from sodium anions (sodide) in liquid tetrahydrofuran (THF). Because the absorption spectra of the sodide reactant, the sodium atom, and the solvated electron products overlap, we first examined the dynamics of the ejected CTTS electron in the infrared to build a detailed model of the CTTS process that allowed us to subtract the spectroscopic contributions of the sodide bleach and the solvated electron and cleanly reveal the spectroscopy of the solvated atom. We find that the neutral sodium species created following CTTS excitation of sodide initially absorbs near 590 nm, the position of the gas-phase sodium D-line, suggesting that it only weakly interacts with the surrounding solvent. We then see a fast solvation process that causes a red-shift of the sodium atom's spectrum in approximately 230 fs, a time scale that matches well with the results of MD simulations of solvation dynamics in liquid THF. After the fast solvation is complete, the neutral sodium atoms undergo a chemical reaction that takes place in approximately 740 fs, as indicated by the observation of an isosbestic point and the creation of a species with a new spectrum. The spectrum of the species created after the reaction then red-shifts on a approximately 10-ps time scale to become the equilibrium spectrum of the THF-solvated sodium atom, which is known from radiation chemistry experiments to absorb near approximately 900 nm. There has been considerable debate as to whether this 900-nm absorbing species is better thought of as a solvated atom or a sodium cation:solvated electron contact pair, (Na+,e-). The fact that we observe the initially created neutral Na atom undergoing a chemical reaction to ultimately become the 900-nm absorbing species suggests that it is better assigned as (Na+,e-). The approximately 10-ps solvation time we observe for this species is an order of magnitude slower than any other solvation process previously observed in liquid THF, suggesting that this species interacts differently with the solvent than the large molecules that are typically used as solvation probes. Together, all of the results allow us to build the most detailed picture to date of the CTTS process of Na- in THF as well as to directly observe the solvation dynamics associated with single sodium atoms in solution.
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Affiliation(s)
- Molly C Cavanagh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
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Saeki A, Kozawa T, Ohnishi Y, Tagawa S. Reactivity between Biphenyl and Precursor of Solvated Electrons in Tetrahydrofuran Measured by Picosecond Pulse Radiolysis in Near-Ultraviolet, Visible, and Infrared. J Phys Chem A 2007; 111:1229-35. [PMID: 17256922 DOI: 10.1021/jp067520m] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The initial decrease of solvated electrons in tetrahydrofuran (THF) upon addition of biphenyl was investigated by picosecond pulse radiolysis. Transient absorption spectra derived from the biphenyl radical anion (centered at 408 and 655 nm) and solvated electrons of THF (infrared) were successfully measured in the wavelength region from 400 to 900 nm by the extension of a femtosecond continuum probe light to near-ultraviolet using a second harmonic generation of Ti:sapphire laser and a CaF2 plate. From the analysis of kinetic traces at 1300 nm considering the overlap of primary solvated electrons and partial biphenyl radical anion, C37, which is defined by the solute concentration to reduce the initial yield of solvated electrons to 1/e, was found to be 87 +/- 3 mM. The rate constant of solvated electrons with biphenyl was determined as 5.8 +/- 0.3 x 10(10) M(-1) s(-1). We demonstrate that the kinetic traces at both 408 nm mainly due to biphenyl radical anion and 1300 nm mainly due to solvated electrons are reproduced with high accuracy and consistency by a simple kinetic analysis. Much higher concentrations of biphenyl (up to 2 M) were examined, showing further increase of the initial yield of biphenyl radical anion accompanying a fast decay component. This observation is discussed in terms of geminate ion recombination, scavenging, delayed geminate ion recombination, and direct ionization of biphenyl at high concentration.
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Affiliation(s)
- Akinori Saeki
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
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Smallwood CJ, Mejia CN, Glover WJ, Larsen RE, Schwartz BJ. A computationally efficient exact pseudopotential method. II. Application to the molecular pseudopotential of an excess electron interacting with tetrahydrofuran (THF). J Chem Phys 2006; 125:074103. [PMID: 16942318 DOI: 10.1063/1.2218835] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In the preceding paper, we presented an analytic reformulation of the Phillips-Kleinman (PK) pseudopotential theory. In the PK theory, the number of explicitly treated electronic degrees of freedom in a multielectron problem is reduced by forcing the wave functions of the few electrons of interest (the valence electrons) to be orthogonal to those of the remaining electrons (the core electrons); this results in a new Schrodinger equation for the valence electrons in which the effects of the core electrons are treated implicitly via an extra term known as the pseudopotential. Although this pseudopotential must be evaluated iteratively, our reformulation of the theory allows the exact pseudopotential to be found without ever having to evaluate the potential energy operator, providing enormous computational savings. In this paper, we present a detailed computational procedure for implementing our reformulation of the PK theory, and we illustrate our procedure on the largest system for which an exact pseudopotential has been calculated, that of an excess electron interacting with a tetrahyrdrofuran (THF) molecule. We discuss the numerical stability of several approaches to the iterative solution for the pseudopotential, and find that once the core wave functions are available, the full e(-)-THF pseudopotential can be calculated in less than 3 s on a relatively modest single processor. We also comment on how the choice of basis set affects the calculated pseudopotential, and provide a prescription for correcting unphysical behavior that arises at long distances if a localized Gaussian basis set is used. Finally, we discuss the effective e(-)-THF potential in detail, and present a multisite analytic fit of the potential that is suitable for use in molecular simulation.
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Affiliation(s)
- C Jay Smallwood
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
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Geminate recombination measurements of solvated electron in THF using laser-synchronized picosecond electron pulse. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Hydrogen/deuterium isotopic substitution neutron diffraction techniques have been used to measure the structural correlation functions of liquid tetrahydrofuran at room temperature. Empirical potential structure refinement (EPSR) has been used to build a three-dimensional model of the liquid structure that is consistent with the experimental data. Analysis to the level of the orientational correlation functions shows that the liquid displays a preference for T-like configurations between the tetrahydrofuran molecules, a local structure that results in void-like regions of approximately 1.25 angstroms radius within the bulk liquid. The surface chemistry of these voids suggests a slightly positive electrostatic character. These findings are consistent with the known propensity of the liquid to solvate free electrons.
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Affiliation(s)
- Daniel T Bowron
- ISIS Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, UK.
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Shoshana O, Pérez Lustres JL, Ernsting NP, Ruhman S. Mapping CTTS dynamics of Na−in tetrahydrofurane with ultrafast multichannel pump–probe spectroscopy. Phys Chem Chem Phys 2006; 8:2599-609. [PMID: 16738713 DOI: 10.1039/b602933g] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using multichannel femtosecond spectroscopy we have followed Na- charge transfer to solvent (CTTS) dynamics in THF solution. Absorption of the primary photoproducts in the visible, resolved here for the first time, consists of an asymmetric triplet centered at 595 nm, which we assign to a metastable incompletely solvated neutral atomic sodium species. Decay of this feature within approximately 1 ps to a broad and structureless solvated neutral is accompanied by broadening and loss of spectral detail. Kinetic analysis shows that both the spectral structure and the decay of this band are independent of the excitation photon frequency in the range 400-800 nm. With different pump-probe polarizations the anisotropy in transient transmission has been charted and its variation with excitation wavelength surveyed. The anisotropies are assigned to the reactant bleach, indicating that due to solvent-induced symmetry breaking, the CTTS absorption band of Na- is made up of discreet orthogonally polarized sub bands. None of the anisotropy in transient absorption could be associated with the photoproduct triplet band even at the earliest measurable time delays. Along with the documented differences in the spatial distribution of ejected electrons across the tested excitation wavelength range, these results lead us to conclude that photoejection is extremely rapid, and that loss of correlations between the departing electron and its neutral core is faster than our time resolution of approximately 60 fs.
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Affiliation(s)
- O Shoshana
- Department of Physical Chemistry, and the Farkas Center for Light Induced Processes, the Hebrew University, Jerusalem, 91904, Israel.
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Holman MW, Yan P, Adams DM, Westenhoff S, Silva C. Ultrafast Spectroscopy of the Solvent Dependence of Electron Transfer in a Perylenebisimide Dimer. J Phys Chem A 2005; 109:8548-52. [PMID: 16834252 DOI: 10.1021/jp0502050] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We investigate the photoinduced intramolecular electron-transfer (IET) behavior of a perylenebisimide dimer in a variety of solvents using femtosecond transient absorption spectroscopy. Overlapping photoinduced absorptions and stimulated emission give rise to complicated traces, but they are well fit with a simple kinetic model. IET rates were found to depend heavily on solvent dielectric constant. Good quantitative agreement with rates derived from fluorescence quantum yield and time-resolved fluorescence measurements was found for forward electron transfer and charge recombination rates.
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Affiliation(s)
- Michael W Holman
- Department of Chemistry, Columbia University, New York, New York 10027, USA
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Taylor MS, Barbera J, Schulz CP, Muntean F, McCoy AB, Lineberger WC. Femtosecond dynamics of Cu(H2O)2. J Chem Phys 2005; 122:54310. [PMID: 15740325 DOI: 10.1063/1.1836759] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ultrafast relaxation dynamics of Cu(H(2)O)(2) is investigated using femtosecond photodetachment-photoionization spectroscopy. In addition, stationary points on the Cu(H(2)O)(2) anion, neutral, and cation potential energy surfaces are characterized by ab initio electronic structure calculations. Electron photodetachment from Cu(-)(H(2)O)(2) initiates the dynamics on the ground-state potential energy surface of neutral Cu(H(2)O)(2). The resulting Cu(H(2)O)(2) complexes experience large-amplitude H(2)O reorientation and dissociation. The time evolution of the Cu(H(2)O)(2) fragmentation products is monitored by time-resolved resonant multiphoton ionization. The parent ion, Cu(+)(H(2)O)(2), is not detected above background levels. The rise to a maximum of the Cu(+) signal from Cu(-)(H(2)O)(2), and the decay of the Cu(+)(H(2)O) signal from Cu(-)(H(2)O)(2) have similar tau approximately 10 ps time dependences to the corresponding signals from Cu(-)(H(2)O), but display clear differences at very short and long times. The experimental observations can be understood in terms of the following picture. Prompt dissociation of H(2)O from nascent Cu(H(2)O)(2) gives rise to a vibrationally excited Cu(H(2)O) complex, which dissociates to Cu+H(2)O due to coupling of H(2)O internal rotation to the dissociation coordinate. This prompt dissociation removes all intra-H(2)O vibrational excitation from the intermediate Cu(H(2)O) fragment, which quenches the long time vibrational predissociation to Cu+H(2)O previously observed in analogous experiments on Cu(-)(H(2)O).
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Affiliation(s)
- Mark S Taylor
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
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40
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Geminate recombination dynamics studied via electron reexcitation: kinetic analysis for anion CTTS photosystems. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.07.094] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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41
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Bezel I, Gaffney KJ, Garrett-Roe S, Liu SH, Miller AD, Szymanski P, Harris CB. Measurement and dynamics of the spatial distribution of an electron localized at a metal–dielectric interface. J Chem Phys 2004; 120:845-56. [PMID: 15267921 DOI: 10.1063/1.1622386] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ability of time- and angle-resolved two-photon photoemission to estimate the size distribution of electron localization in the plane of a metal-adsorbate interface is discussed. It is shown that the width of angular distribution of the photoelectric current is inversely proportional to the electron localization size within the most common approximations in the description of image potential states. The localization of the n=1 image potential state for two monolayers of butyronitrile on Ag(111) is used as an example. For the delocalized n=1 state, the shape of the signal amplitude as a function of momentum parallel to the surface changes rapidly with time, indicating efficient intraband relaxation on a 100 fs time scale. For the localized state, little change was observed. The latter is related to the constant size distribution of electron localization, which is estimated to be a Gaussian with a 15+/-4 A full width at half maximum in the plane of the interface. A simple model was used to study the effect of a weak localization potential on the overall width of the angular distribution of the photoemitted electrons, which exhibited little sensitivity to the details of the potential. This substantiates the validity of the localization size estimate.
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Affiliation(s)
- Ilya Bezel
- Department of Chemistry, University of California and Chemical Sciences Division, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Martini IB, Schwartz BJ. Elucidating the initial dynamics of electron photodetachment from atoms in liquids using variably-time-delayed resonant multiphoton ionization. J Chem Phys 2004; 121:374-9. [PMID: 15260556 DOI: 10.1063/1.1756874] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
We study the photodetachment of electrons from sodium anions in room temperature liquid tetrahydrofuran (THF) using a new type of three-pulse pump-probe spectroscopy. Our experiments use two variably-time-delayed pulses for excitation in what is essentially a resonant 1+1 two-photon ionization: By varying the arrival time of the second excitation pulse, we can directly observe how solvent motions stabilize and trap the excited electron prior to electron detachment. Moreover, by varying the arrival times of the ionization (excitation) and probe pulses, we also can determine the fate of the photoionized electrons and the distance they are ejected from their parent Na atoms. We find that as solvent reorganization proceeds, the second excitation pulse becomes less effective at achieving photoionization, and that the solvent motions that stabilize the excited electron following the first excitation pulse occur over a time of approximately 450 fs. We also find that there is no spectroscopic evidence for significant solvent relaxation after detachment of the electron is complete. In combination with the results of previous experiments and molecular dynamics simulations, the data provide new insight into the role of the solvent in solution-phase electron detachment and charge-transfer-to-solvent reactions.
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Affiliation(s)
- Ignacio B Martini
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095-1569, USA
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Bedard-Hearn MJ, Larsen RE, Schwartz BJ. Understanding Nonequilibrium Solute and Solvent Motions through Molecular Projections: Computer Simulations of Solvation Dynamics in Liquid Tetrahydrofuran (THF). J Phys Chem B 2003. [DOI: 10.1021/jp035846e] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Michael J. Bedard-Hearn
- Department of Chemistry and Biochemistry, University of California, Los Angeles California, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569
| | - Ross E. Larsen
- Department of Chemistry and Biochemistry, University of California, Los Angeles California, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569
| | - Benjamin J. Schwartz
- Department of Chemistry and Biochemistry, University of California, Los Angeles California, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569
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Streltsov AI, Dobrodey NV, Cederbaum LS. Charge transfer effects in molecule–negative ion complexes induced by core ionization. J Chem Phys 2003. [DOI: 10.1063/1.1589002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Barthel ER, Schwartz BJ. Mapping out the conduction band under CTTS transitions: the photodetachment quantum yield of sodide (Na−) in tetrahydrofuran. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(03)00922-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Bedard-Hearn MJ, Larsen RE, Schwartz BJ. Hidden Breakdown of Linear Response: Projections of Molecular Motions in Nonequilibrium Simulations of Solvation Dynamics. J Phys Chem A 2003. [DOI: 10.1021/jp034383+] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wang Z, Shoshana O, Hou B, Ruhman S. Solvent Induced Symmetry Breaking and Relaxation Following Charge Transfer to Solvent Excitation of Na- in Tetrahydrofuran. J Phys Chem A 2003. [DOI: 10.1021/jp014331p] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhaohui Wang
- Department of Physical Chemistry, and the Farkas Center for Light Induced Processes, the Hebrew University, Jerusalem 91904, Israel
| | - Ofir Shoshana
- Department of Physical Chemistry, and the Farkas Center for Light Induced Processes, the Hebrew University, Jerusalem 91904, Israel
| | - Bixue Hou
- Department of Physical Chemistry, and the Farkas Center for Light Induced Processes, the Hebrew University, Jerusalem 91904, Israel
| | - Sanford Ruhman
- Department of Physical Chemistry, and the Farkas Center for Light Induced Processes, the Hebrew University, Jerusalem 91904, Israel
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Renou F, Mostafavi M, Archirel P, Bonazzola L, Pernot P. Solvated Electron Pairing with Earth Alkaline Metals in THF. 1. Formation and Structure of the Pair with Divalent Magnesium. J Phys Chem A 2003. [DOI: 10.1021/jp0216124] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Martini IB, Schwartz BJ. On the insensitivity of the non-adiabatic relaxation of solvated electrons to the details of their local solvent environment. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)00771-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Martini IB, Barthel ER, Schwartz BJ. Manipulating the production and recombination of electrons during electron transfer: Femtosecond control of the charge-transfer-to-solvent (CTTS) dynamics of the sodium anion. J Am Chem Soc 2002; 124:7622-34. [PMID: 12071773 DOI: 10.1021/ja025942d] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The scavenging of a solvated electron represents the simplest possible electron-transfer (ET) reaction. In this work, we show how a sequence of femtosecond laser pulses can be used to manipulate an ET reaction that has only electronic degrees of freedom: the scavenging of a solvated electron by a single atom in solution. Solvated electrons in tetrahydrofuran are created via photodetachment using the charge-transfer-to-solvent (CTTS) transition of sodide (Na(-)). The CTTS process ejects electrons to well-defined distances, leading to three possible initial geometries for the back ET reaction between the solvated electrons and their geminate sodium atom partners (Na(0)). Electrons that are ejected within the same solvent cavity as the sodium atom (immediate contact pairs) undergo back ET in approximately 1 ps. Electrons ejected one solvent shell away from the Na(0) (solvent-separated contact pairs) take hundreds of picoseconds to undergo back ET. Electrons ejected more than one solvent shell from the sodium atom (free solvated electrons) do not recombine on subnanosecond time scales. We manipulate the back ET reaction for each of these geometries by applying a "re-excitation" pulse to promote the localized solvated electron ground state into a highly delocalized excited-state wave function in the fluid's conduction band. We find that re-excitation of electrons in immediate contact pairs suppresses the back ET reaction. The kinetics at different probe wavelengths and in different solvents suggest that the recombination is suppressed because the excited electrons can relocalize into different solvent cavities upon relaxation to the ground state. Roughly one-third of the re-excited electrons do not collapse back into their original solvent cavities, and of these, the majority relocalize into a cavity one solvent shell away. In contrast to the behavior of the immediate pair electrons, re-excitation of electrons in solvent-separated contact pairs leads to an early time enhancement of the back ET reaction, followed by a longer-time recombination suppression. The recombination enhancement results from the improved overlap between the electron and the Na(0) one solvent shell away due to the delocalization of the wave function upon re-excitation. Once the excited state decays, however, the enhanced back ET is shut off, and some of the re-excited electrons relocalize even farther from their geminate partners, leading to a long-time suppression of the recombination; the rates for recombination enhancement and relocalization are comparable. Enhanced recombination is still observed even when the re-excitation pulse is applied hundreds of picoseconds after the initial CTTS photodetachment, verifying that solvent-separated contact pairs are long-lived, metastable entities. Taken together, all these results, combined with the simplicity and convenient spectroscopy of the sodide CTTS system, allow for an unprecedented degree of control that is a significant step toward building a full molecular-level picture of condensed-phase ET reactions.
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Affiliation(s)
- Ignacio B Martini
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
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