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Selvaraj M, Subramani A, Ramanathan K, Richter R, Pal N, Bolognesi P, Avaldi L, Kadhane UR. Fragmentation dynamics of the doubly charged aniline: the source of kinetically excited C nH 3+ ions. Phys Chem Chem Phys 2024; 26:16540-16549. [PMID: 38828709 DOI: 10.1039/d3cp05882d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The goals of this work are to attempt to decipher if an aniline dication can isomerize to a picoline dication in a given astrochemical environment and if the dissociation of such dications could be a source of kinetically hot fragment ions, some of which could be of significance in the interstellar medium. Toward this purpose, the VUV-induced dication dissociation was investigated experimentally using ion-ion coincidence and computationally by optimizing various pathways. Contrary to previous reports, we show here that the dication of aniline is structurally too weak to retain its ring structure while following the dissociation pathways. A fragile open ring structure could lead to all the experimentally observed pathways of noticeable intensity. The significance of this, especially in terms of molecular dynamics, can be assessed by the fact that all the transformations were facilitated by specific hydrogen migration. A clear selectivity is seen where the dication of aniline was found to prefer a rearrangement of hydrogen within the ring rather than transferring from nitrogen to the ring, which is conventionally expected and has to do with the charge state and charge localization.
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Affiliation(s)
| | - Arun Subramani
- Indian Institute of Space Science and Technology, Trivandrum, Kerala, India.
| | - Karthick Ramanathan
- Indian Institute of Space Science and Technology, Trivandrum, Kerala, India.
| | | | | | | | | | - Umesh R Kadhane
- Indian Institute of Space Science and Technology, Trivandrum, Kerala, India.
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López Peña HA, Shusterman JM, Dalkiewicz C, McPherson SL, Dunstan C, Sangroula K, Lao KU, Tibbetts KM. Photodissociation Dynamics of the Highly Stable ortho-Nitroaniline Cation. J Phys Chem A 2024; 128:1634-1645. [PMID: 38411108 PMCID: PMC10926099 DOI: 10.1021/acs.jpca.3c08364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/11/2024] [Accepted: 02/14/2024] [Indexed: 02/28/2024]
Abstract
0rtho-Nitroaniline (ONA) is a model for the insensitive high explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) that shares strong hydrogen bonding character between adjacent nitro and amino groups. This work reports femtosecond time-resolved mass spectrometry (FTRMS) measurements and theoretical calculations that explain the high stability of the ONA cation compared with related nitroaromatic molecules. Ab initio calculations found that the lowest-lying electronic excited state of the ONA cation, D1, lies more than 2 eV above the ground state, and the energetic barriers to rearrangement and dissociation reactions exceed this D1 energy. These theoretical results were confirmed by FTRMS pump-probe measurements showing that (1) fragment ions represented less than 30% of the total ion yield when a 1014 W cm-2, 1300 nm, 20 fs pump pulse was used to ionize ONA; and (2) 3.1 eV (400 nm) photons were required to induce dissociation of the ONA cation. Stronger coupling between the ground D0 and excited D4 states of the ONA cation at the geometry of neutral ONA resulted in a transient enhancement of fragment ion yields at <300 fs pump-probe delay times, prior to relaxation of the ONA cation to its optimal geometry.
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Affiliation(s)
- Hugo A. López Peña
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Jacob M. Shusterman
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Clayton Dalkiewicz
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Shane L. McPherson
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Christine Dunstan
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Kunjal Sangroula
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Ka Un Lao
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
| | - Katharine Moore Tibbetts
- Department of Chemistry, Virginia
Commonwealth University, Richmond, Virginia 23284, United States
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Sun X, Neidlinger LR, Bossert LR, Kolling DR. Inner-Sphere and Outer-Sphere Charge-Transfer Quenching of the Uranyl UO22+(VI) Luminescence, and Kinetics for the Tertiary and Secondary Alcohols Activated Uranyl Emission. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2022.121009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kawaguchi T, Kitagawa K, Toyota K, Kozaki M, Okada K, Nakashima N, Yatsuhashi T. Smallest Organic Tetracation in the Gas Phase: Stability of Multiply Charged Diiodoacetylene Produced in Intense Femtosecond Laser Fields. J Phys Chem A 2021; 125:8014-8024. [PMID: 34491746 DOI: 10.1021/acs.jpca.1c06390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Coulomb explosion imaging, which is the reconstruction of a molecular structure by measuring the three-dimensional momenta of atomic ions formed by a Coulomb explosion of multiply charged molecular cations (MMCs), has been utilized widely. In contrast, intact MMCs, whose properties and reactions are interesting from both fundamental and applied scientific perspectives, themselves have been little explored to date. This study demonstrates that the four-atom molecule diiodoacetylene (DIA) can survive as a long-lived species in the gas phase after the removal of four electrons in intense femtosecond laser fields. The electron configurations of the equilibrium structures of the electronic ground states calculated by the complete active space self-consistent field (CASSCF) method reveal the stability of multiply charged DIA. The dissociation energies are estimated to be 3.01, 3.59, 2.57, 1.82, and 1.61 eV for neutral, cation radical, dication, trication radical, and tetracation, respectively. A fairly deep potential well suggests that a DIA tetracation is metastable toward dissociation, whereas the repulsive potential of a pentacation radical confirms its absence in the mass spectrum. With their sufficiently long lifetimes, minimum number of atoms, and simple dissociation paths, DIA MMCs are promising candidates for further experimental and theoretical investigations of multiply charged ion chemistry.
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Affiliation(s)
- Takashi Kawaguchi
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 Japan
| | - Kosei Kitagawa
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 Japan
| | - Kazuo Toyota
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 Japan
| | - Masatoshi Kozaki
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 Japan
| | - Keiji Okada
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 Japan
| | - Nobuaki Nakashima
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 Japan
| | - Tomoyuki Yatsuhashi
- Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 Japan
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Sun X, Kolling DR, Smythers AL, Deal RA. Investigations of the photochemical charge-transfer reduction of uranyl UO22+(VI) to uranyl UO2+(V) by benzene-1,4-diol (1,4-C6H4(OH)2) and oxalate (C2O42−) by UV–Vis, electron paramagnetic resonance, and luminescence spectroscopies. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2021.120451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Gutsev GL, McPherson SL, López Peña HA, Boateng DA, Gutsev LG, Ramachandran BR, Tibbetts KM. Dissociation of Singly and Multiply Charged Nitromethane Cations: Femtosecond Laser Mass Spectrometry and Theoretical Modeling. J Phys Chem A 2020; 124:7427-7438. [PMID: 32841027 DOI: 10.1021/acs.jpca.0c06545] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dissociation pathways of singly- and multiply charged gas-phase nitromethane cations were investigated with strong-field laser photoionization mass spectrometry and density functional theory computations. There are multiple isomers of the singly charged nitromethane radical cation, several of which can be accessed by rearrangement of the parent CH3-NO2 structure with low energy barriers. While direct cleavage of the C-N bond from the parent nitromethane cation produces NO2+ and CH3+, rearrangement prior to dissociation accounts for fragmentation products including NO+, CH2OH+, and CH2NO+. Extensive Coulomb explosion in fragment ions observed at high laser intensity indicates that rapid dissociation of multiply charged nitromethane cations produces additional species such as CH2+, H+, and NO22+. On the basis of analysis of Coulomb explosion in the mass spectral signals and pathway calculations, sufficiently intense laser fields can remove four or more electrons from nitromethane.
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Affiliation(s)
- Gennady L Gutsev
- Department of Physics, Florida A&M University, Tallahassee, Florida 32307, United States
| | - Shane L McPherson
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Hugo A López Peña
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Derrick Ampadu Boateng
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Lavrenty G Gutsev
- Institute for Micromanufacturing, Louisiana Tech University, Ruston, Louisiana 71272, United States.,Institute of Problems of Chemical Physics of Russian Academy of Sciences, Chernogolovka, Moscow District 142432, Russia
| | - B Ramu Ramachandran
- Institute for Micromanufacturing, Louisiana Tech University, Ruston, Louisiana 71272, United States
| | - Katharine Moore Tibbetts
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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