1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Krylov AI. The Quantum Chemistry of Open-Shell Species. REVIEWS IN COMPUTATIONAL CHEMISTRY 2017. [DOI: 10.1002/9781119356059.ch4] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Anna I. Krylov
- Department of Chemistry; University of Southern California; Los Angeles CA United States
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Bell F, Zimmerman PM, Casanova D, Goldey M, Head-Gordon M. Restricted active space spin-flip (RAS-SF) with arbitrary number of spin-flips. Phys Chem Chem Phys 2013; 15:358-66. [DOI: 10.1039/c2cp43293e] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
5
|
Steinbauer M, Giegerich J, Fischer KH, Fischer I. The photodissociation dynamics of the ethyl radical, C2H5, investigated by velocity map imaging. J Chem Phys 2012; 137:014303. [DOI: 10.1063/1.4731285] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
6
|
|
7
|
Gasser M, Frey JA, Hostettler JM, Bach A, Chen P. Vibronic Structure of the 3s and 3p Rydberg States of the Allyl Radical. J Phys Chem A 2009; 114:4704-11. [DOI: 10.1021/jp907524s] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael Gasser
- Laboratorium für Organische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Jann A. Frey
- Laboratorium für Organische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland
| | | | - Andreas Bach
- Laboratorium für Organische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Peter Chen
- Laboratorium für Organische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland
| |
Collapse
|
8
|
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]
|
9
|
Karpichev B, Reisler H, Krylov AI, Diri K. Effect of Hyperconjugation on Ionization Energies of Hydroxyalkyl Radicals. J Phys Chem A 2008; 112:9965-9. [DOI: 10.1021/jp805250t] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Boris Karpichev
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Hanna Reisler
- 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
| | - Kadir Diri
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| |
Collapse
|
10
|
Krylov AI. Equation-of-motion coupled-cluster methods for open-shell and electronically excited species: the Hitchhiker's guide to Fock space. Annu Rev Phys Chem 2008; 59:433-62. [PMID: 18173379 DOI: 10.1146/annurev.physchem.59.032607.093602] [Citation(s) in RCA: 728] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The equation-of-motion coupled-cluster (EOM-CC) approach is a versatile electronic-structure tool that allows one to describe a variety of multiconfigurational wave functions within single-reference formalism. This review provides a guide to established EOM methods illustrated by examples that demonstrate the types of target states currently accessible by EOM. It focuses on applications of EOM-CC to electronically excited and open-shell species. The examples emphasize EOM's advantages for selected situations often perceived as multireference cases [e.g., interacting states of different nature, Jahn-Teller (JT) and pseudo-JT states, dense manifolds of ionized states, diradicals, and triradicals]. I also discuss limitations and caveats and offer practical solutions to some problematic situations. The review also touches on some formal aspects of the theory and important current developments.
Collapse
Affiliation(s)
- Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA.
| |
Collapse
|
11
|
Shin SK, Dagdigian PJ. Further investigation of the photodissociation dynamics of dichlorocarbene near 248 nm. J Chem Phys 2008; 128:154322. [PMID: 18433224 DOI: 10.1063/1.2908236] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A further investigation of the 248 nm photodissociation of CCl(2), which expands upon our original study of this process [S. K. Shin and P. J. Dagdigian, Phys. Chem. Chem. Phys. 8, 3446 (2006)], is presented. The CCl(2) parent molecule and the CCl photofragment were detected by laser fluorescence excitation in a molecular beam experiment. From the dependence of the CCl(2) signals on the photolysis laser fluence, attenuation cross sections of the 0(0), 1(1), and 2(1) vibrational levels were determined; the cross sections for the excited vibrational levels were found to be significantly smaller than those for the ground vibrational level. The previously observed fragment CCl bimodal rotational state distribution was found to arise from the photolysis of more than one parent molecule. At low CHCl(3) mole fractions in the gas supplied to the pyrolysis beam source, it was concluded that CCl(2) is the photolysis precursor for both low-J and high-J CCl fragments. On the basis of the dependence of the CCl signals on the photolysis laser fluence, ground and vibrationally excited CCl(2), respectively, were assigned as the precursors to these two classes of fragments. The photofragment excitation spectra for low-J and high-J CCl fragments from the photolysis of CCl(2) were recorded in the wavelength range around 248 nm; both were found to be structureless. The 248 nm photodissociation dynamics of CCl(2) is discussed in light of our experimental observations and quantum chemical calculations of the CCl(2) excited electronic states.
Collapse
Affiliation(s)
- Seung Keun Shin
- Department of Chemistry, The Johns Hopkins University, Baltimore, MD 21218-2685, USA
| | | |
Collapse
|
12
|
Fedorov I, Koziol L, Li G, Reisler H, Krylov AI. Vibronic Structure and Ion Core Interactions in Rydberg States of Diazomethane: An Experimental and Theoretical Investigation. J Phys Chem A 2007; 111:13347-57. [DOI: 10.1021/jp0768064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Igor Fedorov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Lucas Koziol
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Guosheng Li
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482
| | - Hanna Reisler
- 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
| |
Collapse
|
13
|
Pitarch-Ruiz J, Sánchez-Marín J, Velasco AM. Full configuration interaction calculation of the low lying valence and Rydberg states of BeH. J Comput Chem 2007; 29:523-32. [PMID: 17722010 DOI: 10.1002/jcc.20811] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The all-electron full configuration interaction (FCI) vertical excitation energies for some low lying valence and Rydberg excited states of BeH are presented in this article. A basis set of valence atomic natural orbitals has been augmented with a series of Rydberg orbitals that have been generated as centered onto the Be atom. The resulting basis set can be described as 4s2p1d/2s1p (Be/H) + 4s4p3d. It allows to calculate Rydberg states up to n= {3,4,5} of the s, p, and d series of Rydberg states. The FCI vertical ionization potential for the same basis set and geometry amounts to 8.298 eV. Other properties such as FCI electric dipole and quadrupole moments and FCI transition dipole and quadrupole moments have also been calculated. The results provide a set of benchmark values for energies, wave functions, properties, and transition properties for the five electron BeH molecule. Most of the states have large multiconfigurational character in spite of their essentially single excited nature and a number of them present an important Rydberg-valence mixing that is achieved through the mixed nature of the particle MO of the single excitations.
Collapse
Affiliation(s)
- J Pitarch-Ruiz
- Institut de Ciencia Molecular, Universitat de València, Campus de Paterna, Paterna E-46980 (Valencia), Spain
| | | | | |
Collapse
|
14
|
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).
Collapse
Affiliation(s)
- Erin S Whitney
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA
| | | | | | | | | |
Collapse
|