1
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Hockey EK, McLane N, Vlahos K, McCaslin LM, Dodson LG. Matrix-formation dynamics dictate methyl nitrite conformer abundance. J Chem Phys 2024; 160:094303. [PMID: 38436440 DOI: 10.1063/5.0188433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/31/2024] [Indexed: 03/05/2024] Open
Abstract
Methyl nitrite has two stable conformational isomers resulting from rotation about the primary C-O-N-O dihedral angle: cis-CH3ONO and trans-CH3ONO, with cis being more stable by ∼5 kJ/mol. The barrier to rotational interconversion (∼45 kJ/mol) is too large for isomerization to occur under ambient conditions. This paper presents evidence of a change in conformer abundance when dilute CH3ONO is deposited onto a cold substrate; the relative population of the freshly deposited cis conformer is seen to increase compared to its gas-phase abundance, measured by in situ infrared spectroscopy. We observe abundance changes depending on the identity of the bath gas (N2, Ar, and Xe) and deposition angle. The observations indicate that the surface properties of the growing matrix influence conformer abundance-contrary to the widely held assumption that conformer abundance in matrices reflects gas-phase abundance. We posit that differences in the angle-dependent host-gas deposition dynamics affect the growing surfaces, causing changes in conformer abundances. Quantum chemistry calculations of the binding energies between CH3ONO and a single bath-gas component reveal that significant energetic stabilization is not observed in 1:1 complexes of N2:CH3ONO, Ar:CH3ONO, or Xe:CH3ONO. From our results, we conclude that the growing surface plays a significant role in trapping cis-CH3ONO more effectively than trans-CH3ONO, likely because cis-CH3ONO is more compact. Taken together, the observations highlight the necessity for careful characterization of conformers in matrix-isolated systems, emphasizing a need for further study into the deposition dynamics and surface structure of chemically inert matrices.
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Affiliation(s)
- Emily K Hockey
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Nathan McLane
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
| | - Korina Vlahos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | | | - Leah G Dodson
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
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2
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Senanayake PS, Syrlybaeva RR, Talipov MR. Unusual In-plane Aromaticity Facilitates Intramolecular Hydrogen Transfer in Long-Bonded cis-Isonitrosyl Methoxide. J Phys Chem A 2022; 126:6826-6833. [PMID: 36049165 DOI: 10.1021/acs.jpca.2c03315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The hydrogen-atom transfer from methoxy radical to nitric oxide, leading to the formation of formaldehyde and nitroxyl, represents a secondary reaction of photodissociation of methyl nitrite, which is used as rocket fuel. In this study, we explored the potential energy profile of the hydrogen-atom transfer using the electronic structure calculations at the DLPNO-CCSD(T)/aug-cc-pVTZ level of theory for two isomeric forms (cis and trans) of the pre-reaction complex. The cis-oriented pre-reaction complex has a weak elongated O─O bond, which gets further elongated in the hydrogen transfer transition state. This O─O bond stabilizes the pre-reaction complex by 32.9 kJ/mol. The O─O-induced stabilization is even greater for the transition state (48.2 kJ/mol), which was unexpected because of the larger O─O distance in the transition state structure. To address this paradox, we performed the electronic structure analysis of the reaction participants using the valence bond (VB) theory, natural resonance theory, topological analysis of the electron density and its derivatives, and analysis of the electron localization function distribution. This combined analysis led to the conclusion that the cis-transition state for hydrogen transfer, instead of being directly stabilized by the O─O interaction, gained substantial stabilization from the in-plane five-center six-electron aromaticity.
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Affiliation(s)
- Punhasa S Senanayake
- Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, United States
| | - Raulia R Syrlybaeva
- Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, United States
| | - Marat R Talipov
- Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, United States
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3
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Thomas S, Blin-Simiand N, Héninger M, Jeanney P, Lemaire J, Magne L, Mestdagh H, Pasquiers S, Louarn E. Insights into non-thermal plasma chemistry of acetone diluted in N 2/O 2 mixtures: a real-time MS experiment. Phys Chem Chem Phys 2022; 24:20553-20564. [PMID: 35997062 DOI: 10.1039/d2cp02119f] [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
Understanding non-thermal plasma reactivity is a complicated task as many reactions take place due to a large energy spectrum. In this work, we used a well-defined photo-triggered non-filamentous discharge to study acetone decomposition in N2/O2 gas mixtures. The plasma reactor is associated to a compact chemical ionization FTICR mass spectrometer (BTrap) in order to identify and quantify in real-time acetone and by-products in the plasma. Presence of oxygen (1 to 5%) decreased notably acetone degradation. A tremendous change is observed in the by-products distribution concomitantly to a global decrease of their total concentration. While main products observed in oxygen-free gas mix are nitrile compounds, in oxygenated media they are replaced by formaldehyde, methanol and ketene. Methanol is maximum for 1% of O2 whereas formaldehyde and ketene concentration reach their maximum value at the highest oxygen concentration tested (5%). A number of nitrate, nitrite and isocyanate organic compounds (C1 and C2) are observed as well with HNO2, HNO3 and HNCO.
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Affiliation(s)
- Sébastien Thomas
- CNRS, Institut de Chimie Physique, Université Paris-Saclay, UMR8000, 91405 Orsay, France.
| | - Nicole Blin-Simiand
- CNRS, Laboratoire de Physique des Gaz et des Plasma, Université Paris-Saclay, UMR8578, 91405 Orsay, France
| | - Michel Héninger
- CNRS, Institut de Chimie Physique, Université Paris-Saclay, UMR8000, 91405 Orsay, France.
| | - Pascal Jeanney
- CNRS, Laboratoire de Physique des Gaz et des Plasma, Université Paris-Saclay, UMR8578, 91405 Orsay, France
| | - Joel Lemaire
- CNRS, Institut de Chimie Physique, Université Paris-Saclay, UMR8000, 91405 Orsay, France.
| | - Lionel Magne
- CNRS, Laboratoire de Physique des Gaz et des Plasma, Université Paris-Saclay, UMR8578, 91405 Orsay, France
| | - Hélène Mestdagh
- CNRS, Institut de Chimie Physique, Université Paris-Saclay, UMR8000, 91405 Orsay, France.
| | - Stéphane Pasquiers
- CNRS, Laboratoire de Physique des Gaz et des Plasma, Université Paris-Saclay, UMR8578, 91405 Orsay, France
| | - Essyllt Louarn
- CNRS, Institut de Chimie Physique, Université Paris-Saclay, UMR8000, 91405 Orsay, France. .,CNRS, Institut de Recherche sur la Catalyse et l'Environnement de Lyon, Université Claude Bernard Lyon 1, UMR5256, 69626 Villeurbanne, France
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4
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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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5
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Chang P, Zhou P, Liu J, Yin S. Theoretical study on autocatalytic reaction in thermal decomposition of nitromethane. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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6
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Understanding the Photolysis of CH 3ONO 2 with the On-the-fly Nonadiabatic Dynamics Simulation at the ADC(2) Level. CHINESE J CHEM PHYS 2022. [DOI: 10.1063/1674-0068/cjcp2201013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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7
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Filming ultrafast roaming-mediated isomerization of bismuth triiodide in solution. Nat Commun 2021; 12:4732. [PMID: 34354075 PMCID: PMC8342516 DOI: 10.1038/s41467-021-25070-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/20/2021] [Indexed: 12/19/2022] Open
Abstract
Roaming reaction, defined as a reaction yielding products via reorientational motion in the long-range region (3 - 8 Å) of the potential, is a relatively recently proposed reaction pathway and is now regarded as a universal mechanism that can explain the unimolecular dissociation and isomerization of various molecules. The structural movements of the partially dissociated fragments originating from the frustrated bond fission at the onset of roaming, however, have been explored mostly via theoretical simulations and rarely observed experimentally. Here, we report an investigation of the structural dynamics during a roaming-mediated isomerization reaction of bismuth triiodide (BiI3) in acetonitrile solution using femtosecond time-resolved x-ray liquidography. Structural analysis of the data visualizes the atomic movements during the roaming-mediated isomerization process including the opening of the Bi-Ib-Ic angle and the closing of Ia-Bi-Ib-Ic dihedral angle, each by ~40°, as well as the shortening of the Ib···Ic distance, following the frustrated bond fission.
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8
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Analysis of the roaming trajectories from the dynamic and kinematic perspectives – A representative study of triatomic systems. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Ford J, Seritan S, Zhu X, Sakano MN, Islam MM, Strachan A, Martínez TJ. Nitromethane Decomposition via Automated Reaction Discovery and an Ab Initio Corrected Kinetic Model. J Phys Chem A 2021; 125:1447-1460. [PMID: 33569957 DOI: 10.1021/acs.jpca.0c09168] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We explore the systematic construction of kinetic models from in silico reaction data for the decomposition of nitromethane. Our models are constructed in a computationally affordable manner by using reactions discovered through accelerated molecular dynamics simulations using the ReaxFF reactive force field. The reaction paths are then optimized to determine reaction rate parameters. We introduce a reaction barrier correction scheme that combines accurate thermochemical data from density functional theory with ReaxFF minimal energy paths. We validate our models across different thermodynamic regimes, showing predictions of gas phase CO and NO concentrations and high-pressure induction times that are similar to experimental data. The kinetic models are analyzed to find fundamental decomposition reactions in different thermodynamic regimes.
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Affiliation(s)
- Jason Ford
- Department of Chemistry and The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Stefan Seritan
- Department of Chemistry and The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Xiaolei Zhu
- Department of Chemistry and The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Michael N Sakano
- School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Md Mahbub Islam
- School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States.,Department of Mechanical Engineering, Wayne State University, Detroit, Michigan 48202, United States
| | - Alejandro Strachan
- School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Todd J Martínez
- Department of Chemistry and The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
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10
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Palazzetti F, Tsai PY. Photodissociation Dynamics of CO-Forming Channels on the Ground-State Surface of Methyl Formate at 248 nm: Direct Dynamics Study and Assessment of Generalized Multicenter Impulsive Models. J Phys Chem A 2021; 125:1198-1220. [PMID: 33507759 DOI: 10.1021/acs.jpca.0c10464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The photodissociation dynamics of methyl formate in the electronic ground state S0, initiated by a 248 nm-wavelength laser, is studied by direct dynamics simulations. We analyze five channels, where four of them have as products CH3OH + CO, one leading to the formation of three fragments, H2CO + H2 + CO, and a channel characterized by a roaming transition state. The analysis of energy distribution among the degrees of freedom of the product and the comparison with experimental results previously published by other groups provide the ingredients to distinguish the examined dissociation pathways. The interpretation of the results proves that the characterization of dissociation mechanisms must rely on a dynamics approach involving multiple electronic states, including considerations on the features of the S1/S0 conical intersection. Here, we also assess the generalized multicenter impulsive model, GMCIM, that has been designed for dissociation processes with exit barriers, and the energy distribution in the products is predicted on the basis of information from the saddle points and the intrinsic reaction coordinates. Main features, advantages, limits, and future perspectives of the method are reported and discussed.
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Affiliation(s)
- Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia 06123, Italy
| | - Po-Yu Tsai
- Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan
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11
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Quasiclassical simulations based on cluster models reveal vibration-facilitated roaming in the isomerization of CO adsorbed on NaCl. Nat Chem 2021; 13:249-254. [PMID: 33462381 DOI: 10.1038/s41557-020-00612-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 11/18/2020] [Indexed: 11/08/2022]
Abstract
The desire to better understand the quantum nature of isomerization led to recent experimental observations of the vibrationally induced isomerization of OC-NaCl(100) to CO-NaCl(100). To investigate the mechanism of this isomerization, we performed dynamics calculations using finite (CO-NaCl)n cluster models. We constructed new potential energy surfaces for CO-NaCl and CO-CO interactions using high-level ab initio data and report key properties of the bare CO-NaCl potential energy surface, which show much in common with the experiment. We investigated the isomerization dynamics using several cluster models and, in all cases, isomerization was seen for highly excited CO vibrational states, in agreement with experiments. A detailed examination of the reaction trajectories indicates that isomerization occurs when the distance between CO and NaCl is larger than the distance at the conventional isomerization saddle point, which is a strong indicator of 'roaming'.
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12
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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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13
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Abstract
Roaming reactions were first clearly identified in photodissociation of formaldehyde 15 years ago, and roaming dynamics are now recognized as a universal aspect of chemical reactivity. These reactions typically involve frustrated near-dissociation of a quasibound system to radical fragments, followed by reorientation at long range and intramolecular abstraction. The consequences can be unexpected formation of molecular products, depletion of the radical pool in chemical systems, and formation of products with unusual internal state distributions. In this review, I examine some current aspects of roaming reactions with an emphasis on experimental results, focusing on possible quantum effects in roaming and roaming dynamics in bimolecular systems. These considerations lead to a more inclusive definition of roaming reactions as those for which key dynamics take place at long range.
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Affiliation(s)
- Arthur G. Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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14
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Roaming Dynamics and Conformational Memory in Photolysis of Formic Acid at 193 nm Using Time-resolved Fourier-transform Infrared Emission Spectroscopy. Sci Rep 2020; 10:4769. [PMID: 32179782 PMCID: PMC7075954 DOI: 10.1038/s41598-020-61642-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 11/28/2019] [Indexed: 11/09/2022] Open
Abstract
In photodissociation of trans-formic acid (HCOOH) at 193 nm, we have observed two molecular channels of CO + H2O and CO2 + H2 by using 1 μs-resolved Fourier-transform infrared emission spectroscopy. With the aid of spectral simulation, the CO spectra are rotationally resolved for each vibrational state (v = 1-8). Each of the resulting vibrational and rotational population distributions is characteristic of two Boltzmann profiles with different temperatures, originating from either transition state pathway or OH-roaming to form the same CO + H2O products. The H2O roaming co-product is also spectrally simulated to understand the interplay with the CO product in the internal energy partitioning. Accordingly, this work has evaluated the internal energy disposal for the CO and H2O roaming products; especially the vibrational-state dependence of the roaming signature is reported for the first time. Further, given a 1 μs resolution, the temporal dependence of the CO/CO2 product ratio at v ≥ 1 rises from 3 to 10 of study, thereby characterizing the effect of conformational memory and well reconciling with the disputed results reported previously between absorption and emission methods.
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15
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Nandi A, Qu C, Bowman JM. Using Gradients in Permutationally Invariant Polynomial Potential Fitting: A Demonstration for CH4 Using as Few as 100 Configurations. J Chem Theory Comput 2019; 15:2826-2835. [DOI: 10.1021/acs.jctc.9b00043] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Apurba Nandi
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Chen Qu
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Joel M. Bowman
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
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16
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Foley CD, Alavi ST, Joalland B, Broderick BM, Dias N, Suits AG. Imaging the infrared multiphoton excitation and dissociation of propargyl chloride. Phys Chem Chem Phys 2019; 21:1528-1535. [PMID: 30617359 DOI: 10.1039/c8cp06668j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Infrared multiphoton excitation is combined with UV excitation and state-resolved probes of Cl(2P3/2), Cl*(2P1/2), and HCl to study the photochemistry of propargyl chloride. The results show evidence both of infrared multiphoton dissociation on the ground electronic state and infrared multiphoton excitation followed by UV dissociation. The results are interpreted with the aid of a full characterization of the stationary points on the ground state using ab initio methods, as well as our recent experimental and theoretical characterization of the UV photochemistry of the molecule. The data suggest elimination of HCl on the ground electronic state produces linear propadienylidene as a coproduct over a roaming-like transition state that accesses the Cl-H-C abstraction geometry. This identification is supported by separate chirped-pulse microwave studies in a quasi-uniform flow also reported here.
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Affiliation(s)
- Casey D Foley
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
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17
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Suits AG. Invited Review Article: Photofragment imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:111101. [PMID: 30501356 DOI: 10.1063/1.5045325] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/25/2018] [Indexed: 06/09/2023]
Abstract
Photodissociation studies in molecular beams that employ position-sensitive particle detection to map product recoil velocities emerged thirty years ago and continue to evolve with new laser and detector technologies. These powerful methods allow application of tunable laser detection of single product quantum states, simultaneous measurement of velocity and angular momentum polarization, measurement of joint product state distributions for the detected and undetected products, coincident detection of multiple product channels, and application to radicals and ions as well as closed-shell molecules. These studies have permitted deep investigation of photochemical dynamics for a broad range of systems, revealed new reaction mechanisms, and addressed problems of practical importance in atmospheric, combustion, and interstellar chemistry. This review presents an historical overview, a detailed technical account of the range of methods employed, and selected experimental highlights illustrating the capabilities of the method.
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Affiliation(s)
- Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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18
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Lin KC, Tsai PY, Chao MH, Nakamura M, Kasai T, Lombardi A, Palazzetti F, Aquilanti V. Roaming signature in photodissociation of carbonyl compounds. INT REV PHYS CHEM 2018. [DOI: 10.1080/0144235x.2018.1488951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan (ROC)
| | - Po-Yu Tsai
- Department of Chemistry, National Chung-Hsing University, Taichung, Taiwan (ROC)
| | - Meng-Hsuan Chao
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
| | - Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
- Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Andrea Lombardi
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Consortium for Computational Molecular and Materials Sciences (CMS)2, Perugia, Italy
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Scuola Normale Superiore di Pisa, Pisa, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome, Italy
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19
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Abstract
The phenomenon of roaming in chemical reactions has now become both commonly observed in experiment and extensively supported by theory and simulations. Roaming occurs in highly-excited molecules when the trajectories of atomic motion often bypass the minimum energy pathway and produce reaction in unexpected ways from unlikely geometries. The prototypical example is the unimolecular dissociation of formaldehyde (H2CO), in which the "normal" reaction proceeds through a tight transition state to yield H2 + CO but for which a high fraction of dissociations take place via a "roaming" mechanism in which one H atom moves far from the HCO, almost to dissociation, and then returns to abstract the second H atom. We review below the theories and simulations that have recently been developed to address and understand this new reaction phenomenon.
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Affiliation(s)
- Joel M Bowman
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University Atlanta, Georgia 30322, USA.
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20
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Góbi S, Crandall PB, Maksyutenko P, Förstel M, Kaiser RI. Accessing the Nitromethane (CH3NO2) Potential Energy Surface in Methanol (CH3OH)–Nitrogen Monoxide (NO) Ices Exposed to Ionizing Radiation: An FTIR and PI-ReTOF-MS Investigation. J Phys Chem A 2018; 122:2329-2343. [DOI: 10.1021/acs.jpca.7b12235] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sándor Góbi
- Department of Chemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
- W. M. Keck Laboratory in Astrochemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
| | - Parker B. Crandall
- Department of Chemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
- W. M. Keck Laboratory in Astrochemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
| | - Pavlo Maksyutenko
- Department of Chemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
- W. M. Keck Laboratory in Astrochemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
| | - Marko Förstel
- Department of Chemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
- W. M. Keck Laboratory in Astrochemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
- W. M. Keck Laboratory in Astrochemistry, University of Hawai‘i at Ma̅noa, Honolulu, Hawaii 96822, United States
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21
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Adachi S, Kohguchi H, Suzuki T. Unravelling the Electronic State of NO 2 Product in Ultrafast Photodissociation of Nitromethane. J Phys Chem Lett 2018; 9:270-273. [PMID: 29257692 DOI: 10.1021/acs.jpclett.7b03032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The primary photochemical reaction of nitromethane (NM) after ππ* excitation is known to be C-N bond cleavage (CH3NO2 + hν → CH3 + NO2). On the other hand, NO2 can be formed in both the ground and excited states, and identification of the electronic state of the NO2 product has been a central subject in the experimental and theoretical studies. Here we present time-resolved photoelectron spectroscopy using vacuum-ultraviolet probe pulses to observe all transient electronic states of NM and the reaction products. The result indicates that ultrafast internal conversion occurs down to S1 and S0 within 24 fs, and the dissociation proceeds on the S1 surface (τdiss ≲ 50 fs), leading to comparable product yields of NO2(A) and NO2(X). The overall dissociation quantum yield within our observation time window (<2 ps) is estimated to be 0.29.
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Affiliation(s)
- Shunsuke Adachi
- Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hiroshi Kohguchi
- Department of Chemistry, Graduate School of Science, Hiroshima University , Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University , Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
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22
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Han Y, Rasulev B, Kilin DS. Photofragmentation of Tetranitromethane: Spin-Unrestricted Time-Dependent Excited-State Molecular Dynamics. J Phys Chem Lett 2017; 8:3185-3192. [PMID: 28618779 DOI: 10.1021/acs.jpclett.7b01330] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study, the photofragmentation dynamics of tetranitromethane (TNM) is explored by a spin-unrestricted time-dependent excited-state molecular dynamics (u-TDESMD) algorithm based on Rabi oscillations and principles similar to trajectory surface hopping, with a midintensity field approximation. The leading order process is represented by the molecule undergoing cyclic excitations and de-excitations. During excitation cycles, the nuclear kinetic energy is accumulated to overcome the dissociation barriers in the reactant and a sequence of intermediates. The dissociation pathway includes the ejection of NO2 groups followed by the formation of NO and CO. The simulated mass spectra at the ab initio level, based on the bond length in possible fragments, are extracted from simulation trajectories. The recently developed methodology has the potential to model and monitor photoreactions with open-shell intermediates and radicals.
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Affiliation(s)
- Yulun Han
- Department of Chemistry, University of South Dakota , Vermillion, South Dakota 57069, United States
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States
| | - Bakhtiyor Rasulev
- Department of Coatings and Polymeric Materials, North Dakota State University , Fargo, North Dakota 58102, United States
| | - Dmitri S Kilin
- Department of Chemistry, University of South Dakota , Vermillion, South Dakota 57069, United States
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States
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23
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Houston PL, Wang X, Ghosh A, Bowman JM, Quinn MS, Kable SH. Formaldehyde roaming dynamics: Comparison of quasi-classical trajectory calculations and experiments. J Chem Phys 2017; 147:013936. [DOI: 10.1063/1.4982823] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Paul L. Houston
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA and Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14852, USA
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Xiaohong Wang
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Aryya Ghosh
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Joel M. Bowman
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Mitchell S. Quinn
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Scott H. Kable
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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24
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25
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Matsugi A, Shiina H. Thermal Decomposition of Nitromethane and Reaction between CH3 and NO2. J Phys Chem A 2017; 121:4218-4224. [DOI: 10.1021/acs.jpca.7b03715] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Akira Matsugi
- National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - Hiroumi Shiina
- National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
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26
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Ma X, Hase WL. Perspective: chemical dynamics simulations of non-statistical reaction dynamics. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0204. [PMID: 28320906 PMCID: PMC5360902 DOI: 10.1098/rsta.2016.0204] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/05/2017] [Indexed: 06/06/2023]
Abstract
Non-statistical chemical dynamics are exemplified by disagreements with the transition state (TS), RRKM and phase space theories of chemical kinetics and dynamics. The intrinsic reaction coordinate (IRC) is often used for the former two theories, and non-statistical dynamics arising from non-IRC dynamics are often important. In this perspective, non-statistical dynamics are discussed for chemical reactions, with results primarily obtained from chemical dynamics simulations and to a lesser extent from experiment. The non-statistical dynamical properties discussed are: post-TS dynamics, including potential energy surface bifurcations, product energy partitioning in unimolecular dissociation and avoiding exit-channel potential energy minima; non-RRKM unimolecular decomposition; non-IRC dynamics; direct mechanisms for bimolecular reactions with pre- and/or post-reaction potential energy minima; non-TS theory barrier recrossings; and roaming dynamics.This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.
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Affiliation(s)
- Xinyou Ma
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
| | - William L Hase
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409, USA
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27
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Maksyutenko P, Förstel M, Crandall P, Sun BJ, Wu MH, Chang AH, Kaiser RI. An isomer-specific study of solid nitromethane decomposition pathways – Detection of aci-nitromethane (H2CNO(OH)) and nitrosomethanol (HOCH2NO) intermediates. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Habershon S. Automated Prediction of Catalytic Mechanism and Rate Law Using Graph-Based Reaction Path Sampling. J Chem Theory Comput 2016; 12:1786-98. [DOI: 10.1021/acs.jctc.6b00005] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Scott Habershon
- Department
of Chemistry and
Centre for Scientific Computing, University of Warwick, Gibbet Hill
Road, Coventry CV4 7AL, United Kingdom
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29
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Tsegaw YA, Sander W, Kaiser RI. Electron Paramagnetic Resonance Spectroscopic Study on Nonequilibrium Reaction Pathways in the Photolysis of Solid Nitromethane (CH3NO2) and D3-Nitromethane (CD3NO2). J Phys Chem A 2016; 120:1577-87. [PMID: 26863093 DOI: 10.1021/acs.jpca.5b12520] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thin films of nitromethane (CH3NO2) along with its isotopically labeled counterpart D3-nitromethane (CD3NO2) were photolyzed at discrete wavelength between 266 nm (4.7 eV) and 121 nm (10.2 eV) to explore the underlying mechanisms involved in the decomposition of model compounds of energetic materials in the condensed phase at 5 K. The chemical modifications of the ices were traced in situ via electron paramagnetic resonance, thus focusing on the detection of (hitherto elusive) reaction intermediates and products with unpaired electrons. These studies revealed the formation of two carbon-centered radicals [methyl (CH3), nitromethyl (CH2NO2)], one oxygen-centered radical [methoxy (CH3O)], two nitrogen-centered radicals [nitrogen monoxide (NO), nitrogen dioxide (NO2)], as well as atomic hydrogen (H). The decomposition products of these channels and the carbon-centered nitromethyl (CH2NO2) radical in particular represent crucial reaction intermediates leading via sequential molecular mass growth processes in the exposed nitromethane samples to complex organic molecules as predicted previously by dynamics calculations. The detection of the nitromethyl (CH2NO2) radical along with atomic hydrogen (H) demonstrated the existence of a high-energy decomposition pathway, which is closed under collisionless conditions in the gas phase.
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Affiliation(s)
| | - Wolfram Sander
- Lehrstuhl für Organische Chemie II, Ruhr-Universitat Bochum , 44801 Bochum, Germany
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa , Honolulu, Hawaii 96822, United States
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30
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Houston PL, Conte R, Bowman JM. Roaming Under the Microscope: Trajectory Study of Formaldehyde Dissociation. J Phys Chem A 2016; 120:5103-14. [DOI: 10.1021/acs.jpca.6b00488] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul L. Houston
- School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Department
of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14852, United States
| | - Riccardo Conte
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
- Dipartimento
di Chimica, Università degli Studi di Milano, 20133 Milano, Italy
| | - Joel M. Bowman
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
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31
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Fernando R, Ariyasingha NM, Suits AG. Imaging NO elimination in the infrared multiphoton dissociation of nitroalkanes and alkyl nitrites. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2015.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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32
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Nelson T, Bjorgaard J, Greenfield M, Bolme C, Brown K, McGrane S, Scharff RJ, Tretiak S. Ultrafast Photodissociation Dynamics of Nitromethane. J Phys Chem A 2016; 120:519-26. [DOI: 10.1021/acs.jpca.5b09776] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tammie Nelson
- Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, United States
| | - Josiah Bjorgaard
- Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, United States
| | - Margo Greenfield
- Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, United States
| | - Cindy Bolme
- Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, United States
| | - Katie Brown
- Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, United States
| | - Shawn McGrane
- Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, United States
| | - R. Jason Scharff
- Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, United States
| | - Sergei Tretiak
- Los Alamos National Laboratory, Los
Alamos, New Mexico 87545, United States
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33
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Wang X, Carter S, Bowman JM. Pruning the Hamiltonian Matrix in MULTIMODE: Test for C2H4 and Application to CH3NO2 Using a New Ab Initio Potential Energy Surface. J Phys Chem A 2015; 119:11632-40. [PMID: 26529348 DOI: 10.1021/acs.jpca.5b09816] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report vibrational self-consistent field/virtual state configuration interaction energies of nitromethane using the code MULTIMODE and a new full-dimensional potential energy surface (PES). The PES is a precise, permutationally invariant linear least-squares fit to 17,049 electronic energies, using the CCSD(T)-F12b method with HaDZ basis (cc-pVDZ basis for H atoms, and aug-cc-pVDZ basis for C, O, N atoms). Nitromethane has 15 vibrational degrees of freedom, including one that is a nearly free internal methyl torsion, which is accurately described by the PES. This torsional mode makes vibrational calculations very challenging and here we present the results of calculations without it. Nevertheless, 14-mode calculations are still challenging and can lead to very large Hamiltonian matrices. To address this issue, we apply a pruning scheme, suggested previously by Handy and Carter, that reduces the size of matrix without sacrificing accuracy in the eigenvalues. The method is briefly described here in the context of partitioning theory. A new and more efficient implementation of it, coded in the latest version of MULTIMODE program, is described. The accuracy and efficiency are demonstrated for 12-mode C2H4 and then applied to CH3NO2. Agreement with available experimental values of the CH3NO2 14 fundamentals is very good. Diffusion Monte Carlo calculations in full dimensionality are done for the zero-point energy and wavefuction. These indicate that the torisonal motion is nearly a free-rotor in this state.
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Affiliation(s)
- Xiaohong Wang
- Department of Chemistry, Emory University , Atlanta Georgia 30322, United States
| | - Stuart Carter
- Department of Chemistry, Emory University , Atlanta Georgia 30322, United States
| | - Joel M Bowman
- Department of Chemistry, Emory University , Atlanta Georgia 30322, United States
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34
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Annesley CJ, Randazzo JB, Klippenstein SJ, Harding LB, Jasper AW, Georgievskii Y, Ruscic B, Tranter RS. Thermal Dissociation and Roaming Isomerization of Nitromethane: Experiment and Theory. J Phys Chem A 2015; 119:7872-93. [DOI: 10.1021/acs.jpca.5b01563] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher J. Annesley
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - John B. Randazzo
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Stephen J. Klippenstein
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Lawrence B. Harding
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Ahren W. Jasper
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Yuri Georgievskii
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Branko Ruscic
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Robert S. Tranter
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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35
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Vereecken L, Glowacki DR, Pilling MJ. Theoretical Chemical Kinetics in Tropospheric Chemistry: Methodologies and Applications. Chem Rev 2015; 115:4063-114. [DOI: 10.1021/cr500488p] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Luc Vereecken
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - David R. Glowacki
- PULSE
Institute and Department of Chemistry, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
- Department
of Computer Science, University of Bristol, Bristol BS8 1UB, United Kingdom
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36
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Chen BJ, Tsai PY, Huang TK, Xia ZH, Lin KC, Chiou CJ, Sun BJ, Chang AHH. Characterization of molecular channel in photodissociation of SOCl2 at 248 nm: Cl2 probing by cavity ring-down absorption spectroscopy. Phys Chem Chem Phys 2015; 17:7838-47. [PMID: 25715942 DOI: 10.1039/c4cp06043a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A primary elimination channel of the chlorine molecule in the one-photon dissociation of SOCl2 at 248 nm was investigated using cavity ring-down absorption spectroscopy (CRDS). By means of spectral simulation, the ratio of the vibrational population in the v = 0, 1, and 2 levels was evaluated to be 1 : (0.10 ± 0.02) : (0.009 ± 0.005), corresponding to a Boltzmann vibrational temperature of 340 ± 30 K. The Cl2 molecular channel was obtained with a quantum yield of 0.4 ± 0.2 from the X(1)A' ground state of SOCl2via internal conversion. The dissociation mechanism differs from a prior study where a smaller yield of <3% was obtained, initiated from the 2(1)A' excited state. Temperature-dependence measurements of the Cl2 fragment turn out to support our mechanism. With the aid of ab initio potential energy calculations, two dissociation routes to the molecular products were found, including one synchronous dissociation pathway via a three-center transition state (TS) and the other sequential dissociation pathway via a roaming-mediated isomerization TS. The latter mechanism with a lower energy barrier dominates the dissociation reaction.
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Affiliation(s)
- Bo-Jung Chen
- Department of Chemistry, National Taiwan University, Taipei, Taiwan.
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37
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Tsai PY, Lin KC. Insight into photofragment vector correlation by a multi-center impulsive model. Phys Chem Chem Phys 2015; 17:19592-601. [DOI: 10.1039/c5cp03079j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A multi-center impulsive model has been recently developed to characterize the dynamic feature of fragment vector correlation in photodissociation of formaldehyde, H2CO → CO + H2, via both transition state and roaming pathways.
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Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry
- National Chung Hsing University
- Taichung 402
- Taiwan
| | - King-Chuen Lin
- Department of Chemistry
- National Taiwan University
- and Institute of Atomic and Molecular Sciences
- Taipei 106
- Taiwan
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38
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Maksyutenko P, Muzangwa LG, Jones BM, Kaiser RI. Lyman α photolysis of solid nitromethane (CH3NO2) and D3-nitromethane (CD3NO2) – untangling the reaction mechanisms involved in the decomposition of model energetic materials. Phys Chem Chem Phys 2015; 17:7514-27. [DOI: 10.1039/c4cp05759g] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solid nitromethane and D3-nitromethane ices were exposed to Lyman α photons to investigate the mechanism involved in the decomposition of energetic materials in the condensed phase.
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39
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Morsa D, Gabelica V, Rosu F, Oomens J, De Pauw E. Dissociation Pathways of Benzylpyridinium "Thermometer" Ions Depend on the Activation Regime: An IRMPD Spectroscopy Study. J Phys Chem Lett 2014; 5:3787-3791. [PMID: 26278748 DOI: 10.1021/jz501903b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The dissociation of benzylpyridinium "thermometer" ions is widely used to calibrate the internal energy of ions produced in mass spectrometry. The fragmentation mechanism is usually believed to yield a benzylium cation, although recent studies suggest the possibility of a rearrangement leading to the tropylium isomer, which would compromise the accuracy of energy calibrations. In this study, we used IRMPD spectroscopy to probe the dissociation pathways of the p-(tert-butyl)benzylpyridinium ion. Our results show that the formation of both benzylium and tropylium products is feasible depending on the activation regime and on the reaction time scale. Varying the trapping delays in the hexapole gives insight into a rearrangement mechanism occurring through consecutive reactions with an isomerization from benzylium to tropylium. Our work provides experimental validations for the established calibration procedure and highlights the adequacy of IRMPD spectroscopy to qualitatively resolve gas-phase rearrangement kinetics.
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Affiliation(s)
- Denis Morsa
- †Mass Spectrometry Laboratory, University of Liege, B6c Sart-Tilman, B-4000 Liege, Belgium
| | - Valérie Gabelica
- †Mass Spectrometry Laboratory, University of Liege, B6c Sart-Tilman, B-4000 Liege, Belgium
| | - Frédéric Rosu
- †Mass Spectrometry Laboratory, University of Liege, B6c Sart-Tilman, B-4000 Liege, Belgium
| | - Jos Oomens
- ‡Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525ED Nijmegen, The Netherlands
- §Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Edwin De Pauw
- †Mass Spectrometry Laboratory, University of Liege, B6c Sart-Tilman, B-4000 Liege, Belgium
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40
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Prozument K, Suleimanov YV, Buesser B, Oldham JM, Green WH, Suits AG, Field RW. A Signature of Roaming Dynamics in the Thermal Decomposition of Ethyl Nitrite: Chirped-Pulse Rotational Spectroscopy and Kinetic Modeling. J Phys Chem Lett 2014; 5:3641-3648. [PMID: 26278732 DOI: 10.1021/jz501758p] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chirped-pulse (CP) Fourier transform rotational spectroscopy is uniquely suited for near-universal quantitative detection and structural characterization of mixtures that contain multiple molecular and radical species. In this work, we employ CP spectroscopy to measure product branching and extract information about the reaction mechanism, guided by kinetic modeling. Pyrolysis of ethyl nitrite, CH3CH2ONO, is studied in a Chen type flash pyrolysis reactor at temperatures of 1000-1800 K. The branching between HNO, CH2O, and CH3CHO products is measured and compared to the kinetic models generated by the Reaction Mechanism Generator software. We find that roaming CH3CH2ONO → CH3CHO + HNO plays an important role in the thermal decomposition of ethyl nitrite, with its rate, at 1000 K, comparable to that of the radical elimination channel CH3CH2ONO → CH3CH2O + NO. HNO is a signature of roaming in this system.
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Affiliation(s)
| | | | - Beat Buesser
- §IBM Research, Smarter Cities Technology Centre, Dublin 15, Ireland
| | - James M Oldham
- ∥Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | | | - Arthur G Suits
- ∥Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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41
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Affiliation(s)
- Joel M. Bowman
- Department of Chemistry, Emory University, Atlanta, GA, USA
- Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, GA, USA
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