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Word MD, López Peña HA, Ampadu Boateng D, McPherson SL, Gutsev GL, Gutsev LG, Lao KU, Tibbetts KM. Ultrafast Dynamics of Nitro-Nitrite Rearrangement and Dissociation in Nitromethane Cation. J Phys Chem A 2022; 126:879-888. [PMID: 35133840 DOI: 10.1021/acs.jpca.1c10288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report new insights into the ultrafast rearrangement and dissociation dynamics of nitromethane cation (NM+) using pump-probe measurements, electronic structure calculations, and ab initio molecular dynamics simulations. The "roaming" nitro-nitrite rearrangement (NNR) pathway involving large-amplitude atomic motion, which has been previously described for neutral nitromethane, is demonstrated for NM+. Excess energy resulting from initial population of the electronically excited D2 state of NM+ upon strong-field ionization provides the necessary energy to initiate NNR and subsequent dissociation into NO+. Both pump-probe measurements and molecular dynamics simulations are consistent with the completion of NNR within 500 fs of ionization with dissociation into NO+ and OCH3 occurring ∼30 fs later. Pump-probe measurements indicate that NO+ formation is in competition with the direct dissociation of NM+ to CH3+ and NO2. Electronic structure calculations indicate that a strong D0 → D1 transition can be excited at 650 nm when the C-N bond is stretched from its equilibrium value (1.48 Å) to 1.88 Å. On the other hand, relaxation of the NM+ cation after ionization into D0 occurs in less than 50 fs and results in observation of intact NM+. Direct dissociation of the equilibrium NM+ to produce NO2+ and CH3 can be induced with 650 nm excitation via a weakly allowed D0 → D2 transition.
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Affiliation(s)
- Mi'Kayla D Word
- 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
| | - Shane L McPherson
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Gennady L Gutsev
- Department of Physics, Florida A&M University, Tallahassee, Florida 32307, United States
| | - Lavrenty G Gutsev
- Institute for Problems of Chemical Physics of the Russian Academy of Sciences, Chernogolovka 142432, Russia
| | - 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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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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Mayer PM, Guest MF, Rennie EE, Cooper L, Shpinkova LG, Holland DM, Shaw DA. Threshold ionization and dissociation oft-butylamine. CAN J CHEM 2010. [DOI: 10.1139/v09-150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The threshold photoelectron spectrum of t-butylamine, recorded between 8 and 28 eV, is reported for the first time. The spectrum was compared to orbital ionization energies calculated at the OVGF/cc-pVTZ level of theory. The adiabatic and vertical ionization energies of the outermost orbital (made up primarily of the nitrogen p orbital) are 8.48 ± 0.02 and 9.40 ± 0.02 eV, respectively. Threshold photoelectron photoion coincidence spectra were recorded between 8.5 and 35 eV, and appearance energies for 15 fragment ions were obtained. The lowest energy dissociation is the loss of a methyl group to form the (CH3)2CNH2+ion. RRKM fitting of this dissociation leads to a ΔfH298for (CH3)2CNH2+of 603 ± 3 kJ mol–1. This value is ~10 kJ mol–1higher than the previously derived value of Lossing et al. (based on an electron ionization appearance energy value) and the G3B3 estimate. Together with the proton affinity value of 932.3 kJ mol–1, the present ΔfH298leads to a ΔfH298for 2-propanimine (CH3)2C=NH of 5.3 kJ mol–1, which can be compared to a value of –5.7 kJ mol–1(based on the Lossing et al. (CH3)2CNH2+ΔfH298) and a G3B3 value of –0.3 kJ mol–1. At photon energies above 26 eV, there is evidence for the dissociative double ionization of t-butylamine forming either the singlet or triplet state of the dication.
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Affiliation(s)
- Paul M. Mayer
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada, K1N 6N5
- Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, UK
- Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK
- Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
- Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD, UK
| | - Martyn F. Guest
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada, K1N 6N5
- Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, UK
- Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK
- Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
- Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD, UK
| | - Emma E. Rennie
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada, K1N 6N5
- Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, UK
- Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK
- Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
- Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD, UK
| | - Louise Cooper
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada, K1N 6N5
- Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, UK
- Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK
- Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
- Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD, UK
| | - Larisa G. Shpinkova
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada, K1N 6N5
- Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, UK
- Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK
- Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
- Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD, UK
| | - David M.P. Holland
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada, K1N 6N5
- Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, UK
- Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK
- Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
- Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD, UK
| | - David A. Shaw
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada, K1N 6N5
- Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, UK
- Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK
- Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
- Daresbury Laboratory, Daresbury, Warrington, Cheshire, WA4 4AD, UK
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Mayer PM, Guest MF, Cooper L, Shpinkova LG, Rennie EE, Holland DMP, Shaw DA. Long Bonds and Short Barriers: Ionization and Isomerization of Alkyl Nitriles. J Phys Chem A 2009; 114:867-78. [DOI: 10.1021/jp9096524] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Paul M. Mayer
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada K1N 6N5, Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, U.K., Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K., Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia, and Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - Martyn F. Guest
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada K1N 6N5, Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, U.K., Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K., Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia, and Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - Louise Cooper
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada K1N 6N5, Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, U.K., Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K., Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia, and Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - Larisa G. Shpinkova
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada K1N 6N5, Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, U.K., Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K., Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia, and Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - Emma E. Rennie
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada K1N 6N5, Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, U.K., Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K., Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia, and Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - David M. P. Holland
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada K1N 6N5, Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, U.K., Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K., Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia, and Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - David A. Shaw
- Department of Chemistry, University of Ottawa, 10 Marie-Curie, Ottawa, Canada K1N 6N5, Advanced Research Computing, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3NB Wales, U.K., Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, U.K., Department of Nuclear Spectroscopy Methods, Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia, and Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
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