1
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Tsuchida H, Tezuka T, Kai T, Matsuya Y, Majima T, Saito M. Liquid water radiolysis induced by secondary electrons generated from MeV-energy carbon ions. J Chem Phys 2024; 161:104503. [PMID: 39254164 DOI: 10.1063/5.0227465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Accepted: 08/26/2024] [Indexed: 09/11/2024] Open
Abstract
Fast ion beams induce damage to deoxyribonucleic acid (DNA) by chemical products, including secondary electrons, produced from interaction with liquid water in living cells. However, the production process of these chemical products in the Bragg peak region used in particle therapy is not fully understood. To investigate this process, we conducted experiments to evaluate the radiolytic yields produced when a liquid water jet in vacuum is irradiated with MeV-energy carbon beams. We used secondary ion mass spectrometry to measure the products, such as hydronium cations (H3O+) and hydroxyl anions (OH-), produced along with ·OH radicals, which are significant inducers of DNA damage formation. In addition, we simulated the ionization process in liquid water by incident ions and secondary electrons using a Monte Carlo code for radiation transport. Our results showed that secondary electrons, rather than incident ions, are the primary cause of ionization in water. We found that the production yield of H3O+ or OH- was linked to the frequency of ionization by secondary electrons in water, with these electrons having energies between 10.9 and 550 eV. These electrons are responsible for ionizing the outer-shell electrons of water molecules. Finally, we present that the elementary processes contribute to advancing radiation biophysics and biochemistry, which study the formation mechanism of DNA damage.
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Affiliation(s)
- Hidetsugu Tsuchida
- Department of Nuclear Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
- Quantum Science and Engineering Center, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Tomoya Tezuka
- Department of Nuclear Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takeshi Kai
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Naka-gun, Ibaraki 319-1195, Japan
| | - Yusuke Matsuya
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Naka-gun, Ibaraki 319-1195, Japan
- Faculty of Health Sciences, Hokkaido University, Kita-12 Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Takuya Majima
- Department of Nuclear Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Manabu Saito
- Department of Nuclear Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
- Quantum Science and Engineering Center, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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2
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Schnorr K, Belina M, Augustin S, Lindenblatt H, Liu Y, Meister S, Pfeifer T, Schmid G, Treusch R, Trost F, Slavíˇek P, Moshammer R. Direct tracking of ultrafast proton transfer in water dimers. SCIENCE ADVANCES 2023; 9:eadg7864. [PMID: 37436977 PMCID: PMC10337913 DOI: 10.1126/sciadv.adg7864] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/08/2023] [Indexed: 07/14/2023]
Abstract
Upon ionization, water forms a highly acidic radical cation H2O+· that undergoes ultrafast proton transfer (PT)-a pivotal step in water radiation chemistry, initiating the production of reactive H3O+, OH[Formula: see text] radicals, and a (hydrated) electron. Until recently, the time scales, mechanisms, and state-dependent reactivity of ultrafast PT could not be directly traced. Here, we investigate PT in water dimers using time-resolved ion coincidence spectroscopy applying a free-electron laser. An extreme ultraviolet (XUV) pump photon initiates PT, and only dimers that have undergone PT at the instance of the ionizing XUV probe photon result in distinct H3O+ + OH+ pairs. By tracking the delay-dependent yield and kinetic energy release of these ion pairs, we measure a PT time of (55 ± 20) femtoseconds and image the geometrical rearrangement of the dimer cations during and after PT. Our direct measurement shows good agreement with nonadiabatic dynamics simulations for the initial PT and allows us to benchmark nonadiabatic theory.
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Affiliation(s)
- Kirsten Schnorr
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
- Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland
| | - Michal Belina
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague 6, Czech Republic
| | - Sven Augustin
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
- Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland
| | - Hannes Lindenblatt
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Yifan Liu
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Severin Meister
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Thomas Pfeifer
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Georg Schmid
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Rolf Treusch
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Florian Trost
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Petr Slavíˇek
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague 6, Czech Republic
| | - Robert Moshammer
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
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3
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Zhang X, Ren X, Zhong Y, Chingin K, Chen H. Rapid and sensitive detection of acetone in exhaled breath through the ambient reaction with water radical cations. Analyst 2021; 146:5037-5044. [PMID: 34231556 DOI: 10.1039/d1an00402f] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The levels of acetone and other ketones in exhaled human breath can be associated with various metabolic conditions, e.g. ketosis, lung cancer, dietary fat loss and diabetes. In this study, ketones in breath samples were charged through the reaction with water radical cations to form [M + H2O]˙+ ions, which were detected by mass spectrometry. Our experimental data indicate that under the optimized experimental conditions, the limit of detection for acetone using our approach is 0.14 ng L-1 (∼0.06 ppb). The linear dynamic range of detection spans four orders of magnitude. The developed approach was applied to real-time semi-quantitative analysis of acetone in the exhaled breath of human volunteers, revealing significantly higher levels of acetone in the breath of smokers compared to non-smokers. The developed approach features the obviation of sample collection, easy operation, high speed of analysis (10 s per run), high sensitivity, and spectral interpretation, which indicates the potential of ambient corona discharge ionization mass spectrometry as a selective, sensitive and noninvasive technique for the determination of exhaled ketones in clinical diagnosis including lung cancer, diabetes, etc.
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Affiliation(s)
- Xiaoping Zhang
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, East China University of Technology, Nanchang, 330013, P. R. China.
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Mi D, Cui J, Kuang S, Dong X, Lu H. Facile Atmospheric Generation of Water Radical Cations via
TiO
2
‐Nanoneedle Arrays for Aromatic Hydrocarbon Detection Based on Corona Discharge. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Dongbo Mi
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation East China University of Technology Nanchang 330013 China
| | - Jinhaojie Cui
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation East China University of Technology Nanchang 330013 China
| | - Siliang Kuang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry Jilin University Changchun 130012 China
| | - Xiaofeng Dong
- Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation East China University of Technology Nanchang 330013 China
| | - Haiyan Lu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry Jilin University Changchun 130012 China
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5
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León I, Montero R, Longarte A, Fernández JA. Revisiting the Spectroscopy of Water Dimer in Jets. J Phys Chem Lett 2021; 12:1316-1320. [PMID: 33535759 PMCID: PMC9157493 DOI: 10.1021/acs.jpclett.0c03001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Laser spectroscopy in jets is one of the main sources of structural data from molecular aggregates. Consequently, numerous and sophisticated experimental systems have been developed to extract precise information, which is usually interpreted in the light of quantum mechanical calculations. However, even with the most sophisticated experiments, it is sometimes difficult to interpret the experimental results. We present here the example of water dimer and how after almost 70 years, the assignment of its mass-resolved IR spectrum still generates controversy that extends toward the mechanism of ionization of water aggregates.
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Affiliation(s)
- Iker León
- Grupo
de Espectroscopía Molecular (GEM), Edificio Quifima, Unidad Asociada CSIC, Universidad de Valladolid, 47005 Valladolid, Spain
| | - Raúl Montero
- SGIKER
Laser Facility, University of the Basque
Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Spain
| | - Asier Longarte
- Department
of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Spain
| | - José A. Fernández
- Department
of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, Leioa 48940, Spain
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6
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Zhang X, Ren X, Chingin K, Xu J, Yan X, Chen H. Mass spectrometry distinguishing C=C location and cis/trans isomers: A strategy initiated by water radical cations. Anal Chim Acta 2020; 1139:146-154. [DOI: 10.1016/j.aca.2020.09.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/05/2020] [Accepted: 09/14/2020] [Indexed: 11/29/2022]
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7
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Water Radical Cations in the Gas Phase: Methods and Mechanisms of Formation, Structure and Chemical Properties. Molecules 2020; 25:molecules25153490. [PMID: 32751962 PMCID: PMC7435662 DOI: 10.3390/molecules25153490] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 12/02/2022] Open
Abstract
Water radical cations, (H2O)n+•, are of great research interest in both fundamental and applied sciences. Fundamental studies of water radical reactions are important to better understand the mechanisms of natural processes, such as proton transfer in aqueous solutions, the formation of hydrogen bonds and DNA damage, as well as for the discovery of new gas-phase reactions and products. In applied science, the interest in water radicals is prompted by their potential in radiobiology and as a source of primary ions for selective and sensitive chemical ionization. However, in contrast to protonated water clusters, (H2O)nH+, which are relatively easy to generate and isolate in experiments, the generation and isolation of radical water clusters, (H2O)n+•, is tremendously difficult due to their ultra-high reactivity. This review focuses on the current knowledge and unknowns regarding (H2O)n+• species, including the methods and mechanisms of their formation, structure and chemical properties.
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8
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Choi HW, Kim KK, Jeong BG, Song JK, Park SM. Structures and infrared photodissociation of [(aniline)-(methanol)-(water) 2] . SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 220:117119. [PMID: 31141781 DOI: 10.1016/j.saa.2019.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/30/2019] [Accepted: 05/10/2019] [Indexed: 06/09/2023]
Abstract
The structures of [(aniline)-(methanol)-(water)2]+ were investigated by infrared spectroscopy coupled with linear tandem mass spectrometry. We suggest the most stable structure of [(aniline)-(methanol)-(water)2]+ through infrared photodissociation spectra supported by the density functional theory calculations at the level of ωB97X-D/cc-pVQZ. Methanol and one water molecule formed hydrogen bonding with the amino group of aniline, while the other water formed hydrogen bonding with methanol. Upon infrared excitation of [(aniline)-(methanol)-(water)2]+, the water molecule connected to methanol turned out to be preferentially ejected, although the total internal energy in the cluster ion was large enough to dissociate other solvent molecules. This unique dissociation feature was attributed to the significant difference in the dissociation rates as obtained by the Rice-Ramsperger-Kassel-Marcus theory calculations as well as structural restriction.
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Affiliation(s)
- Hyun Wook Choi
- Department of Chemistry, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Kuk Ki Kim
- Department of Chemistry, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Bong Gyu Jeong
- Department of Chemistry, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Jae Kyu Song
- Department of Chemistry, Kyung Hee University, Seoul 02447, Republic of Korea.
| | - Seung Min Park
- Department of Chemistry, Kyung Hee University, Seoul 02447, Republic of Korea.
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9
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Bourgalais J, Roussel V, Capron M, Benidar A, Jasper AW, Klippenstein SJ, Biennier L, Le Picard SD. Low Temperature Kinetics of the First Steps of Water Cluster Formation. PHYSICAL REVIEW LETTERS 2016; 116:113401. [PMID: 27035301 DOI: 10.1103/physrevlett.116.113401] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Indexed: 06/05/2023]
Abstract
We present a combined experimental and theoretical low temperature kinetic study of water cluster formation. Water cluster growth takes place in low temperature (23-69 K) supersonic flows. The observed kinetics of formation of water clusters are reproduced with a kinetic model based on theoretical predictions for the first steps of clusterization. The temperature- and pressure-dependent association and dissociation rate coefficients are predicted with an ab initio transition state theory based master equation approach over a wide range of temperatures (20-100 K) and pressures (10^{-6}-10 bar).
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Affiliation(s)
- J Bourgalais
- Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 263 avenue Général Leclerc, 35042 Rennes cedex, France
| | - V Roussel
- Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 263 avenue Général Leclerc, 35042 Rennes cedex, France
| | - M Capron
- Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 263 avenue Général Leclerc, 35042 Rennes cedex, France
| | - A Benidar
- Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 263 avenue Général Leclerc, 35042 Rennes cedex, France
| | - A W Jasper
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, USA
| | - S J Klippenstein
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - L Biennier
- Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 263 avenue Général Leclerc, 35042 Rennes cedex, France
| | - S D Le Picard
- Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 263 avenue Général Leclerc, 35042 Rennes cedex, France
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10
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Apicella B, Li X, Passaro M, Spinelli N, Wang X. Multiphoton ionization of large water clusters. J Chem Phys 2014; 140:204313. [DOI: 10.1063/1.4878663] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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11
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Shepperson B, Liu J, Ellis AM, Yang S. Communication: Electron impact ionization of binary H2O∕X clusters in helium nanodroplets: an ab initio perspective. J Chem Phys 2012. [PMID: 23205973 DOI: 10.1063/1.4769810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In a recent experiment (H(2)O)(n)∕X(m) binary clusters (where X = Ar, N(2), CO, CO(2), and several other molecules) were formed in superfluid helium nanodroplets and investigated by electron impact mass spectrometry [Liu et al., Phys. Chem. Chem. Phys. 13, 13920 (2011)]. The addition of dopant X was found to affect the branching ratio between H(3)O(+)(H(2)O)(n) and (H(2)O)(+)(n+2) formation. Specifically, the addition of CO increased the proportion of protonated water cluster ions, whereas dopants such as Ar, N(2), and CO(2), had the opposite effect. In this work ab initio calculations have been performed on [X(H(2)O)(2)](+) ions, where X = Ar, N(2), CO, and CO(2), to try and explain this distinct behavior. CO is found to be unique in that it forms a HOCO-H(3)O(+) unit in the most stable cationic complexes where the binding between HO and CO is stronger than that between H(3)O(+) and OH. Thus, on purely energetic grounds, loss of HOCO rather than CO should be the preferred fragmentation process. No comparable chemistry occurs when X = Ar, N(2), or CO(2) and so the co-dopant requires less energy to depart than OH. The calculations therefore account for the experimental observations and provide evidence that HOCO formation is induced in helium droplets containing (H(2)O)(n) clusters and co-doped with CO when subject to electron impact ionization.
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Affiliation(s)
- Benjamin Shepperson
- Department of Chemistry, University of Leicester, Leicester LE1 7RH, United Kingdom
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12
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Segarra-Martí J, Merchán M, Roca-Sanjuán D. Ab initiodetermination of the ionization potentials of water clusters (H2O)n(n= 2−6). J Chem Phys 2012; 136:244306. [DOI: 10.1063/1.4730301] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Denifl S, Zappa F, Mähr I, Mauracher A, Probst M, Urban J, Mach P, Bacher A, Bohme DK, Echt O, Märk TD, Scheier P. Ionization of doped helium nanodroplets: complexes of C60 with water clusters. J Chem Phys 2010; 132:234307. [PMID: 20572705 DOI: 10.1063/1.3436721] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Water clusters are known to undergo an autoprotonation reaction upon ionization by photons or electron impact, resulting in the formation of (H(2)O)(n)H(3)O(+). Ejection of OH cannot be quenched by near-threshold ionization; it is only partly quenched when clusters are complexed with inert gas atoms. Mass spectra recorded by electron ionization of water-doped helium droplets show that the helium matrix also fails to quench OH loss. The situation changes drastically when helium droplets are codoped with C(60). Charged C(60)-water complexes are predominantly unprotonated; C(60)(H(2)O)(4)(+) and (C(60))(2)(H(2)O)(4)(+) appear with enhanced abundance. Another intense ion series is due to C(60)(H(2)O)(n)OH(+); dehydrogenation is proposed to be initiated by charge transfer between the primary He(+) ion and C(60). The resulting electronically excited C(60)(+*) leads to the formation of a doubly charged C(60)-water complex either via emission of an Auger electron from C(60)(+*), or internal Penning ionization of the attached water complex, followed by charge separation within {C(60)(H(2)O)(n)}(2+). This mechanism would also explain previous observations of dehydrogenation reactions in doped helium droplets. Mass-analyzed ion kinetic energy scans reveal spontaneous (unimolecular) dissociation of C(60)(H(2)O)(n)(+). In addition to the loss of single water molecules, a prominent reaction channel yields bare C(60)(+) for sizes n=3, 4, or 6. Ab initio Hartree-Fock calculations for C(60)-water complexes reveal negligible charge transfer within neutral complexes. Cationic complexes are well described as water clusters weakly bound to C(60)(+). For n=3, 4, or 6, fissionlike desorption of the entire water complex from C(60)(H(2)O)(n)(+) energetically competes with the evaporation of a single water molecule.
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Affiliation(s)
- S Denifl
- Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold Franzens Universität, 6020 Innsbruck, Austria
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14
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Adoui L, Legendre S, Tarisien M, Cassimi A, Galassi ME, Giglio E, Gervais B. High LET highly charged ion-induced ionization and fragmentation of water molecules and clusters. ACTA ACUST UNITED AC 2007. [DOI: 10.1088/1742-6596/88/1/012023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Dong F, Heinbuch S, Rocca JJ, Bernstein ER. Dynamics and fragmentation of van der Waals clusters: (H2O)n, (CH3OH)n, and (NH3)n upon ionization by a 26.5eV soft x-ray laser. J Chem Phys 2006; 124:224319. [PMID: 16784286 DOI: 10.1063/1.2202314] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A tabletop soft x-ray laser is applied for the first time as a high energy photon source for chemical dynamics experiments in the study of water, methanol, and ammonia clusters through time of flight mass spectroscopy. The 26.5 eV/photon laser (pulse time duration of approximately 1 ns) is employed as a single photon ionization source for the detection of these clusters. Only a small fraction of the photon energy is deposited in the cluster for metastable dissociation of cluster ions, and most of it is removed by the ejected electron. Protonated water, methanol, and ammonia clusters dominate the cluster mass spectra. Unprotonated ammonia clusters are observed in the protonated cluster ion size range 2< or =n< or =22. The unimolecular dissociation rate constants for reactions involving loss of one neutral molecule are calculated to be (0.6-2.7)x10(4), (3.6-6.0)x10(3), and (0.8-2.0)x10(4) s(-1) for the protonated water (9< or =n< or =24), methanol (5< or =n< or =10), and ammonia (5< or =n< or =18) clusters, respectively. The temperatures of the neutral clusters are estimated to be between 40 and 200 K for water clusters (10< or =n< or =21), and 50-100 K for methanol clusters (6< or =n< or =10). Products with losses of up to five H atoms are observed in the mass spectrum of the neutral ammonia dimer. Large ammonia clusters (NH(3))(n) (n>3) do not lose more than three H atoms in the photoionization/photodissociation process. For all three cluster systems studied, single photon ionization with a 26.5 eV photon yields near threshold ionization. The temperature of these three cluster systems increases with increasing cluster size over the above-indicated ranges.
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Affiliation(s)
- F Dong
- NSF ERC for Extreme Ultraviolet Science and Technology and Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
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16
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Fletcher JS, Lockyer NP, Vickerman JC. C60, Buckminsterfullerene: its impact on biological ToF-SIMS analysis. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2461] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Felicíssimo VC, Guimarães FF, Gel'mukhanov F, Cesar A, Agren H. The principles of infrared-x-ray pump-probe spectroscopy. Applications on proton transfer in core-ionized water dimers. J Chem Phys 2005; 122:094319. [PMID: 15836140 DOI: 10.1063/1.1860312] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In this paper we derive the basic physics underlying infrared-x-ray pump-probe spectroscopy (IR, infrared). Particular features of the spectroscopy are highlighted and discussed, such as dependence on phase of the infrared pulse, duration and delay time of the x-ray pulse, and molecular orientation. Numerical applications are carried out for the water dimer using wave packet techniques. It is shown that core ionization of the donor oxygen of the water dimer results in a drastic change of the potential with the global minimum placed in the proton transfer region. The results of the modeling indicate that IR-x-ray pump-probe spectroscopy can be used to study the dynamics of proton transfer in this core-ionized state, and that, contrary to conventional core level photoelectron spectroscopy, x-ray core-ionization driven by an IR field is a proper method to explore the proton transfer in a system like the water dimer. We observe that the trajectory of the nuclear wave packet in the ground state potential well is strongly affected by the absolute phase of the IR pulse.
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Affiliation(s)
- V C Felicíssimo
- Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm, Sweden.
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18
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Steinkellner O, Noack F, Ritze HH, Radloff W, Hertel IV. Ultrafast predissociation dynamics of water molecules excited to the electronic C̃ and D̃ states. J Chem Phys 2004; 121:1765-70. [PMID: 15260726 DOI: 10.1063/1.1760732] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Two-photon excitation with femtosecond laser pulses in the spectral range 240-250 nm was used to prepare vapor phase H(2)O and D(2)O in the C (1)B(1) and D (1)A(1) states. Both states are predissociated via the B (1)A(1) state, forming excited OH/OD(A (2)Sigma(+)) as well as ground state OH/OD(X (2)Pi). We used ultrashort infrared probe pulses (1.65-2.42 microm) to control the ratio between these excited and ground state fragments originating from the dissociation process. Time resolved detection of the OH/OD(A (2)Sigma(+)) --> OH/OD(X (2)Pi) fluorescence allows us to monitor the dynamics of the predissociation. For the heterogeneous predissociation out of the C(1)B(1) state life times of (0.5 +/- 0.1) ps and (1.2 +/- 0.1) ps were found for H(2)O and D(2)O, respectively. The purely homogeneous character of the predissociation out of the D (1)A(1) state was monitored.
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Affiliation(s)
- O Steinkellner
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2a, 12489 Berlin, Germany.
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Pelc A, Michalak L. Electron ionization study of ammonia micro-clusters. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2000; 14:1455-1461. [PMID: 10931537 DOI: 10.1002/1097-0231(20000830)14:16<1455::aid-rcm47>3.0.co;2-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An electron impact ion source on a double focusing sector field mass spectrometer was used to investigate ammonia micro-clusters produced by the adiabatic free jet expansion of ammonia gas. The appearance energies for [NH(3)](n)(+), n </= 9, ions have been determined. Results of measurements of appearance pressures of selected clusters are described for a range of operating conditions. An empirical formula describing the ammonia clusters production is proposed. Copyright 2000 John Wiley & Sons, Ltd.
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Affiliation(s)
- A Pelc
- Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
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