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Matthaei CT, Mukhopadhyay DP, Röder A, Poisson L, Fischer I. Photodissociation of the trichloromethyl radical: photofragment imaging and femtosecond photoelectron spectroscopy. Phys Chem Chem Phys 2022; 24:928-940. [PMID: 34913455 DOI: 10.1039/d1cp04084g] [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
Halogen-containing radicals play a key role in catalytic reactions leading to stratospheric ozone destruction, thus their photochemistry is of considerable interest. Here we investigate the photodissociation dynamics of the trichloromethyl radical, CCl3 after excitation in the ultraviolet. While the primary processes directly after light absorption are followed by femtosecond-time resolved photoionisation and photoelectron spectroscopy, the reaction products are monitored by photofragment imaging using nanosecond-lasers. The dominant reaction is loss of a Cl atom, associated with a CCl2 fragment. However, the detection of Cl atoms is of limited value, because in the pyrolysis CCl2 is formed as a side product, which in turn dissociates to CCl + Cl. We therefore additionally monitored the molecular fragments CCl2 and CCl by photoionisation at 118.2 nm and disentangled the contributions from various processes. A comparison of the CCl images with control experiments on CCl2 suggest that the dissociation to CCl + Cl2 contributes to the photochemistry of CCl3.
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Affiliation(s)
- Christian T Matthaei
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Anja Röder
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany. .,LIDYL, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | - Lionel Poisson
- LIDYL, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France. .,Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d*Orsay, 91405, Orsay, France
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Reaction of CH2Cl radical with O2 in solid para-hydrogen: Infrared spectrum of gauche-CH2ClOO radical. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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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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Scrape PG, Roberts TD, Lee SH, Butler LJ. Dissociation Pathways of the CH2CH2ONO Radical: NO2 + Ethene, NO + Oxirane, and a Non-Intrinsic Reaction Coordinate HNO + Vinoxy Pathway. J Phys Chem A 2016; 120:4973-87. [PMID: 27124098 DOI: 10.1021/acs.jpca.5b12669] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We first characterize the dissociation pathways of BrCH2CH2ONO, a substituted alkyl nitrite, upon photoexcitation at 193 nm under collision-free conditions, in a crossed laser-molecular beam scattering apparatus using vacuum ultraviolet photoionization detection. Three primary photodissociation pathways occur: photoelimination of HNO, leading to the products HNO + BrCH2CHO; C-Br bond photofission, leading to Br + CH2CH2ONO; and O-NO bond photofission, leading to NO + BrCH2CH2O. The data show that alkyl nitrites can eliminate HNO via a unimolecular mechanism in addition to the commonly accepted bulk disproportionation mechanism. Some of the products from the primary photodissociation pathways are highly vibrationally excited, so we then probe the product branching from the unimolecular dissociation of these unstable intermediates. Notably, the vibrationally excited CH2CH2ONO radicals undergo two channels predicted by statistical transition-state theory, and an additional non-intrinsic reaction coordinate channel, HNO elimination. CH2CH2ONO is formed with high rotational energy; by employing rotational models based on conservation of angular momentum, we predict, and verify experimentally, the kinetic energies of stable CH2CH2ONO radicals and the angular distribution of dissociation products. The major dissociation pathway of CH2CH2ONO is NO2 + ethene, and some of the NO2 is formed with sufficient internal energy to undergo further photodissociation. Nascent BrCH2CHO and CH2Br are also photodissociated upon absorption of a second 193 nm photon; we derive the kinetic energy release of these dissociations based on our data, noting similarities to the analogous photodissociation of ClCH2CHO and CH2Cl.
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Affiliation(s)
- Preston G Scrape
- The James Franck Institute and Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States
| | - Trevor D Roberts
- The James Franck Institute and Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States
| | - Shih-Huang Lee
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan, Republic of China
| | - Laurie J Butler
- The James Franck Institute and Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States
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Miyamoto Y, Tsubouchi M, Momose T. Infrared Spectroscopy of Chloromethyl Radical in Solid Parahydrogen and Its Nuclear Spin Conversion. J Phys Chem A 2013; 117:9510-7. [DOI: 10.1021/jp312122p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yuki Miyamoto
- Department
of Chemistry, and ‡Department of Physics and Astronomy, The University of British Columbia, 2036 Main Mall, Vancouver,
British Columbia V6T 1Z1, Canada
| | - Masaaki Tsubouchi
- Department
of Chemistry, and ‡Department of Physics and Astronomy, The University of British Columbia, 2036 Main Mall, Vancouver,
British Columbia V6T 1Z1, Canada
| | - Takamasa Momose
- Department
of Chemistry, and ‡Department of Physics and Astronomy, The University of British Columbia, 2036 Main Mall, Vancouver,
British Columbia V6T 1Z1, Canada
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Multiphoton dissociation and vibrational mediated dissociation of chlorinated methanes, CH4−nCln (n=2, 3, 4) at 355nm. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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7
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Chichinin AI, Gericke KH, Kauczok S, Maul C. Imaging chemical reactions – 3D velocity mapping. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350903235045] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Reisler H, Krylov AI. Interacting Rydberg and valence states in radicals and molecules: experimental and theoretical studies. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350902989170] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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9
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Shin SK, Dagdigian PJ. Formation of the CH fragment in the 193nm photodissociation of CHCl. J Chem Phys 2008; 128:064309. [DOI: 10.1063/1.2837664] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Whitney ES, Haeber T, Schuder MD, Blair AC, Nesbitt DJ. High-resolution infrared studies in slit supersonic discharges: CH2 stretch excitation of jet-cooled CH2Cl radical. J Chem Phys 2006; 125:054303. [PMID: 16942209 DOI: 10.1063/1.2208612] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
First high-resolution infrared spectra are presented for jet-cooled CH2 35Cl and CH2 37Cl radicals in the symmetric (nu1) CH2 stretching mode. A detailed spectral assignment yields refined lower and upper state rotational constants, as well as fine structure spin-rotation parameters from least-squares fits to the sub-Doppler line shapes for individual transitions. The rotational constants are consistent with a nearly planar structure, but do not exclude substantial large amplitude bending motion over a small barrier to planarity accessible with zero-point excitation. High level coupled cluster (singles/doubles/triples) calculations, extrapolated to the complete basis set limit, predict a slightly nonplanar equilibrium structure (theta approximately 11 degrees), with a vibrationally adiabatic treatment of the bend coordinate yielding a v = 1<--0 anharmonic frequency (393 cm(-1)) in excellent agreement with matrix studies (nu(bend) approximately 400 cm(-1)). The antisymmetric CH2 stretch vibration is not observed despite high sensitivity detection (signal to noise ratio >20:1) in the symmetric stretch band. This is consistent with density functional theory intensity calculations indicating a >35-fold smaller antisymmetric stretch transition moment for CH2Cl, and yet contrasts dramatically with high-resolution infrared studies of CH2F radical, for which both symmetric and antisymmetric CH2 stretches are observed in a nearly 2:1 intensity ratio. A simple physical model is presented based on a competition between bond-dipole and "charge-sloshing" contributions to the transition moment, which nicely explains the trends in CH2X symmetric versus asymmetric stretch intensities as a function of electron withdrawing group (X = D,Br,Cl,F).
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Affiliation(s)
- Erin S Whitney
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA
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Ashfold MNR, Nahler NH, Orr-Ewing AJ, Vieuxmaire OPJ, Toomes RL, Kitsopoulos TN, Garcia IA, Chestakov DA, Wu SM, Parker DH. Imaging the dynamics of gas phase reactions. Phys Chem Chem Phys 2006; 8:26-53. [PMID: 16482242 DOI: 10.1039/b509304j] [Citation(s) in RCA: 240] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ion imaging methods are making ever greater impact on studies of gas phase molecular reaction dynamics. This article traces the evolution of the technique, highlights some of the more important breakthroughs with regards to improving image resolution and in image processing and analysis methods, and then proceeds to illustrate some of the many applications to which the technique is now being applied--most notably in studies of molecular photodissociation and of bimolecular reaction dynamics.
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13
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Sharma P, Vatsa R, Maity D, Kulshreshtha S. Laser induced photodissociation of CH2Cl2 and CH2Br2 at 355 nm: an experimental and theoretical study. Chem Phys Lett 2003. [DOI: 10.1016/j.cplett.2003.10.055] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Levchenko SV, Demyanenko AV, Dribinski VL, Potter AB, Reisler H, Krylov AI. Rydberg–valence interactions in CH2Cl→CH2+Cl photodissociation: Dependence of absorption probability on ground state vibrational excitation. J Chem Phys 2003. [DOI: 10.1063/1.1568076] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Levchenko SV, Krylov AI. Electronic Structure of Halogen-Substituted Methyl Radicals: Equilibrium Geometries and Vibrational Spectra of CH2Cl and CH2F. J Phys Chem A 2002. [DOI: 10.1021/jp020275w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sergey V. Levchenko
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Anna I. Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
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16
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Potter A, Dribinski V, Demyanenko A, Reisler H. Competitive channels in the jet-cooled photodissociation of the CH2Cl radical. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)01175-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Levchenko SV, Krylov AI. Electronic structure of halogen-substituted methyl radicals: Excited states of CH2Cl and CH2F. J Chem Phys 2001. [DOI: 10.1063/1.1400143] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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