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Crane SW, Lee JWL, Ashfold MNR, Rolles D. Molecular photodissociation dynamics revealed by Coulomb explosion imaging. Phys Chem Chem Phys 2023. [PMID: 37335247 DOI: 10.1039/d3cp01740k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Coulomb explosion imaging (CEI) methods are finding ever-growing use as a means of exploring and distinguishing the static stereo-configurations of small quantum systems (molecules, clusters, etc). CEI experiments initiated by ultrafast (femtosecond-duration) laser pulses also allow opportunities to track the time-evolution of molecular structures, and thereby advance understanding of molecular fragmentation processes. This Perspective illustrates two emerging families of dynamical studies. 'One-colour' studies (employing strong field ionisation driven by intense near infrared or single X-ray or extreme ultraviolet laser pulses) afford routes to preparing multiply charged molecular cations and exploring how their fragmentation progresses from valence-dominated to Coulomb-dominated dynamics with increasing charge and how this evolution varies with molecular size and composition. 'Two-colour' studies use one ultrashort laser pulse to create electronically excited neutral molecules (or monocations), whose structural evolution is then probed as a function of pump-probe delay using an ultrafast ionisation pulse along with time and position-sensitive detection methods. This latter type of experiment has the potential to return new insights into not just molecular fragmentation processes but also charge transfer processes between moieties separating with much better defined stereochemical control than in contemporary ion-atom and ion-molecule charge transfer studies.
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Affiliation(s)
- Stuart W Crane
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
| | - Jason W L Lee
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | | | - Daniel Rolles
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
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Thapa B, Schlegel HB. Molecular dynamics of methylamine, methanol, and methyl fluoride cations in intense 7 micron laser fields. J Phys Chem A 2014; 118:10067-72. [PMID: 25268677 DOI: 10.1021/jp507251e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fragmentation and isomerization of methylamine (CH3NH2(+)), methanol (CH3OH(+)), and methyl fluoride (CH3F(+)) cations by short, intense laser pulses have been studied by ab initio classical trajectory calculations. Born-Oppenheimer molecular dynamics (BOMD) on the ground-state potential energy surface were calculated with the CAM-B3LYP/6-31G(d,p) level of theory for the cations in a four-cycle laser pulse with a wavelengths of 7 μm and intensities of 0.88 × 10(14) and 1.7 × 10(14) W/cm(2). The most abundant reaction path was CH2X(+) + H (63-100%), with the second most favorable path being HCX(+) + H2 (0-33%), followed by isomerization to CH2XH(+) (0-8%). C-X cleavage after isomerization was observed only in methyl fluoride. Compared to random orientation, CH3X(+) with the C-X aligned with the laser polarization gained energy nearly twice as much from laser fields. The percentage of CH3(+) + X dissociation increased when the C-X bond was aligned with the laser field. Alignment also increased the branching ratio for H2 elimination in CH3NH2(+) and CH3OH(+) and for isomerization in CH3OH(+).
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Affiliation(s)
- Bishnu Thapa
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
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Thapa B, Schlegel HB. Molecular Dynamics of Methanol Monocation (CH3OH+) in Strong Laser Fields. J Phys Chem A 2014; 118:1769-76. [DOI: 10.1021/jp410091b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bishnu Thapa
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - H. Bernhard Schlegel
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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Matsuda A, Fushitani M, Thomas RD, Zhaunerchyk V, Hishikawa A. Multiple Explosion Pathways of the Deuterated Benzene Trication in 9-fs Intense Laser Fields. J Phys Chem A 2009; 113:2254-60. [DOI: 10.1021/jp806466x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Akitaka Matsuda
- Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8585, Japan, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki, Aichi 444-8585, Japan, Department of Physics, Albanova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden, and PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Mizuho Fushitani
- Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8585, Japan, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki, Aichi 444-8585, Japan, Department of Physics, Albanova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden, and PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Richard D. Thomas
- Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8585, Japan, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki, Aichi 444-8585, Japan, Department of Physics, Albanova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden, and PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Vitali Zhaunerchyk
- Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8585, Japan, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki, Aichi 444-8585, Japan, Department of Physics, Albanova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden, and PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Akiyoshi Hishikawa
- Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8585, Japan, The Graduate University for Advanced Studies (SOKENDAI), Myodaiji, Okazaki, Aichi 444-8585, Japan, Department of Physics, Albanova University Centre, Stockholm University, SE-106 91 Stockholm, Sweden, and PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
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Itakura R, Liu P, Furukawa Y, Okino T, Yamanouchi K, Nakano H. Two-body Coulomb explosion and hydrogen migration in methanol induced by intense 7 and 21fs laser pulses. J Chem Phys 2007; 127:104306. [PMID: 17867746 DOI: 10.1063/1.2768958] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Two-body Coulomb explosion with the C-O bond breaking of methanol induced by intense laser pulses with the duration of Delta t=7 and 21 fs is investigated by the coincidence momentum imaging method. When Delta t=7 fs, the angular distribution of recoil vectors of the fragment ions for the direct C-O bond breaking pathway, CH(3)OH(2+)-->CH(3) (+)+OH(+), exhibits a peak deflected from the laser polarization direction by 30 degrees -45 degrees , and the corresponding angular distribution for the migration pathway, CH(2)OH(2) (+)-->CH(2) (+)+H(2)O(+), in which one hydrogen migrates from the carbon site to the oxygen site prior to the C-O bond breaking, exhibits almost the same profile. When the laser pulse duration is stretched to Delta t=21 fs, the angular distributions for the direct and migration pathways exhibit a broad peak along the laser polarization direction probably due to the dynamical alignment and/or the change in the double ionization mechanism; that is, from the nonsequential double ionization to the sequential double ionization. However, the extent of the anisotropy in the migration pathway is smaller than that in the direct pathway, exhibiting a substantial effect of hydrogen atom migration in the dissociative ionization of methanol interacting with the linearly polarized intense laser field.
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Affiliation(s)
- Ryuji Itakura
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Wu D, Wang Q, Cheng X, Jin M, Li X, Hu Z, Ding D. Effect of Cation Absorption on Ionization/Dissociation of Cycloketone Molecules in a Femtosecond Laser Field. J Phys Chem A 2007; 111:9494-8. [PMID: 17711268 DOI: 10.1021/jp073313q] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mass spectra of a series of cycloketone molecules, cyclopentanone (CPO), cyclohexanone (CHO), cycloheptanone (CHPO), and cyclooctanone (COO) are measured in a 788 or 394 nm laser field with 90 fs pulse duration and the intensity ranging from 5 x 10(13) W/cm(2) to 2 x 10(14) W/cm(2). At 788 nm, a dominated parent ion peak and some weak peaks from the fragment ions C(n)H(m)+ are observed for CPO and CHO (a ratio P(+)/T(+), the parent ion yield to the total ion yield, is 81.6% and 52.6%, respectively). But the extensive fragment ion peaks are observed with the greatly reduced parent ion peak for CHPO (P(+)/T(+) = 5.5%) and that are even hard to be identified for COO. These observations are interpreted explicitly in the frame of the significant resonant effect of their cation photoabsorption on ionization and dissociation of these molecules. The present work also suggests that a nonadiabatic ionization occurs with a nuclear rearrangement due to the H movement in these molecules during the ionization in an intense femtosecond laser field.
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Affiliation(s)
- Di Wu
- Institute of Atomic and Molecular Physics, Jilin University, 2699 Qianjin Street, Changchun 130012, China
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