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González-Vázquez J, García GA, Chicharro DV, Bañares L, Poullain SM. Evidencing an elusive conical intersection in the dissociative photoionization of methyl iodide. Chem Sci 2024; 15:3203-3213. [PMID: 38425510 PMCID: PMC10901492 DOI: 10.1039/d3sc04065h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 12/23/2023] [Indexed: 03/02/2024] Open
Abstract
The valence-shell dissociative photoionization of methyl iodide (CH3I) is studied using double imaging photoelectron photoion coincidence (i2 PEPICO) spectroscopy in combination with highly-tunable synchrotron radiation from synchrotron SOLEIL. The experimental results are complemented by new high-level ab initio calculations of the potential energy curves of the relevant electronic states of the methyl iodide cation (CH3I+). An elusive conical intersection is found to mediate internal conversion from the initially populated first excited state, CH3I+(Ã2A1), into the ground cationic state, leading to the formation of methyl ions (CH3+). The reported threshold photoelectron spectrum for CH3+ reveals that the ν5 scissors vibrational mode promotes the access to this conical intersection and hence, the transfer of population. An intramolecular charge transfer takes place simultaneously, prior to dissociation. Upon photoionization into the second excited cationic state, CH3I+(B̃2E), a predissociative mechanism is shown to lead to the formation of atomic I+.
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Affiliation(s)
- Jesús González-Vázquez
- Departamento de Química, Facultad de Ciencias, Universidad Autónoma de Madrid Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid 28049 Madrid Spain
| | - Gustavo A García
- Synchrotron SOLEIL L'Orme des Merisiers, St. Aubin, BP 48 91192 Gif-sur-Yvette France
| | - David V Chicharro
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid 28040 Madrid Spain
| | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid 28040 Madrid Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience) Cantoblanco 28049 Madrid Spain
| | - Sonia Marggi Poullain
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid 28040 Madrid Spain
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2
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Murillo-Sánchez ML, Marggi Poullain S, Loriot V, Corrales ME, Bañares L. Femtosecond predissociation dynamics of ethyl iodide in the B-band. Phys Chem Chem Phys 2019; 21:15695-15704. [PMID: 31271396 DOI: 10.1039/c9cp02992c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond time-resolved velocity map ion imaging experiments are reported on the second absorption band (B-band) of ethyl iodide at 201.19 and 200.08 nm, corresponding to the 000 and 1810 transitions, i.e., the origin of the band and the first most intense vibronic state assigned to one quantum of excitation in the methyl torsion mode. Electronic predissociation lifetimes and the temporal evolution of the anisotropy have been determined by time-resolved resonance-enhanced multiphoton ionization of iodine and ethyl fragment images. A shorter lifetime measured at the origin of the band in comparison with methyl iodide indicates that predissociation in ethyl iodide is more favorable due to a stronger coupling between the initial Rydberg state and the valence repulsive state correlating with the dissociation fragments. Moreover, vibrational activity in the methyl torsion in the Rydberg state seems to enhance the probability of transfer of population to the valence repulsive state leading to a faster dissociation. The perpendicular character of the transition at early times and the loss of anisotropy as a function of time have been determined from the time-resolved angular distributions of the iodine and ethyl ion images. The initial anisotropy value is consistent with a purely perpendicular transition compatible with the excitation of the [6A'', 7A'] states with a minor parallel component to the C-I bond. The loss of initial anisotropy over time highlights the parent molecular rotation during predissociation and is compatible with a rotational temperature of the parent molecule of 100 K.
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Affiliation(s)
- Marta L Murillo-Sánchez
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Sonia Marggi Poullain
- Departamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Vincent Loriot
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumiére Matiére, F-69622, Villeurbanne, France
| | - Maria E Corrales
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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3
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Marggi Poullain S, Recio P, Chicharro DV, Rubio-Lago L, González-Vázquez J, Bañares L. Dynamics of the photodissociation of ethyl iodide from the origin of the B band. A slice imaging study. Phys Chem Chem Phys 2019; 21:14250-14260. [PMID: 30565605 DOI: 10.1039/c8cp06482b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photodissociation dynamics and stereodynamics of ethyl iodide from the origin of the second absorption B-band have been investigated combining pulsed slicFe imaging with resonance enhanced multiphoton ionization (REMPI) detection of all fragments, I(2P3/2), I*(2P1/2) and C2H5. The I*(2P1/2) atom action spectrum recorded as a function of the excitation wavelength permits one to identify and select the 0 origin of this band at 201.19 nm (49 704 cm-1). Translational energy distributions and angular distributions for all fragments and semiclassical Dixon's bipolar moments for the C2H5 fragment are presented and discussed along with high-level ab initio calculations of potential energy curves as a function of the C-I distance. A predissociative mechanism governs the dynamics where in a first step a bound Rydberg state corresponding to the 5pπI→ 6sI transition is populated by the 201.19 nm-photon absorption. A curve crossing with a repulsive state located within the Franck-Condon geometry leads to direct dissociation into the major channel C2H5 + I*(2P1/2). A small amount of I(2P3/2) atoms is nevertheless observed and presumably attributed to a second curve crossing with a repulsive state from the A-band.
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Affiliation(s)
- Sonia Marggi Poullain
- Departamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Pedro Recio
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - David V Chicharro
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Luis Rubio-Lago
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Jesús González-Vázquez
- Departamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain and Institute for Advanced Research in Chemical Sciences (IAdChem), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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4
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Multidimensional Analysis of Time-Resolved Charged Particle Imaging Experiments. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8081227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We present a tutorial to realize a multidimensional fitting procedure capable of extracting all the relevant information contained in a sequence of charged particle images acquired as a function of time in femtosecond pump–probe experiments. The images are reproduced using a 3D fitting method, which provides the velocity (or center-of-mass kinetic energy) and angular distributions contained in the images and their time evolution. A detailed example of the method is shown through the analysis of the time-resolved predissociation dynamics of CH3I on the B-band origin (Gitzinger et al., J. Chem. Phys.2010, 133, 234313). We show that the multidimensional approach is essential for the analysis of complex images that contain several overlapping contributions where reduced dimensionality analyses cannot provide a reliable description of the features present in the image sequence. This methodology can be generalized to many types of multidimensional data analysis.
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5
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Baumann A, Rompotis D, Schepp O, Wieland M, Drescher M. Time-Resolved Dissociation Dynamics of Iodomethane Resulting from Rydberg and Valence Excitation. J Phys Chem A 2018; 122:4779-4784. [DOI: 10.1021/acs.jpca.8b01248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arne Baumann
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
| | | | - Oliver Schepp
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
| | - Marek Wieland
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
- Center for Free-Electron Laser Science—CFEL, Hamburg 22607, Germany
| | - Markus Drescher
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
- Center for Free-Electron Laser Science—CFEL, Hamburg 22607, Germany
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6
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Wittenbrink N, Eisfeld W. Extension of the effective relativistic coupling by asymptotic representation (ERCAR) approach to multi-dimensional potential energy surfaces: 3D model for CH3I. J Chem Phys 2018. [DOI: 10.1063/1.5011757] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Nils Wittenbrink
- Theoretische Chemie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
| | - Wolfgang Eisfeld
- Theoretische Chemie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
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7
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Corrales ME, de Nalda R, Bañares L. Strong laser field control of fragment spatial distributions from a photodissociation reaction. Nat Commun 2017; 8:1345. [PMID: 29116091 PMCID: PMC5677097 DOI: 10.1038/s41467-017-01139-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 08/22/2017] [Indexed: 11/10/2022] Open
Abstract
The notion that strong laser light can intervene and modify the dynamical processes of matter has been demonstrated and exploited both in gas and condensed phases. The central objective of laser control schemes has been the modification of branching ratios in chemical processes, under the philosophy that conveniently tailored light can steer the dynamics of a chemical mechanism towards desired targets. Less explored is the role that strong laser control can play on chemical stereodynamics, i.e. the angular distribution of the products of a chemical reaction in space. This work demonstrates for the case of methyl iodide that when a molecular bond breaking process takes place in the presence of an intense infrared laser field, its stereodynamics is profoundly affected, and that the intensity of this laser field can be used as an external knob to control it.
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Affiliation(s)
- María E Corrales
- Departamento de Química Física (Unidad Asociada de I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Rebeca de Nalda
- Instituto de Química Física Rocasolano, CSIC, C/ Serrano 119, 28006, Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física (Unidad Asociada de I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
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8
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Corrales ME, Shternin PS, Rubio-Lago L, de Nalda R, Vasyutinskii OS, Bañares L. Femtosecond Time-Resolved Photofragment Rotational Angular Momentum Alignment in Electronic Predissociation Dynamics. J Phys Chem Lett 2016; 7:4458-4463. [PMID: 27786494 DOI: 10.1021/acs.jpclett.6b01874] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This Letter presents an experimental and theoretical study of femtosecond time-resolved vector correlations in methyl iodide (CH3I) electronic predissociation via the second absorption B-band at 201.2 nm. The time evolution of the phenomenological anisotropy parameters βl was determined from time-resolved photofragment angular distributions obtained by means of the femtosecond laser pump-probe technique coupled with velocity map imaging detection of vibrational ground-state CH3(ν = 0) fragments and spin-orbit excited I*(2P1/2) atoms. Theoretical interpretation of the experimental results was performed on the basis of a fitting procedure using quasiclassical theory, which elucidates vector correlations in photodissociation of symmetric top molecules. The results of the fitting are in very good agreement with the experimental data and demonstrate the important role of molecular excited-state lifetimes, parent molecule and methyl fragment rotations, and methyl fragment angular momentum alignment on the time-dependent electronic predissociation dynamics.
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Affiliation(s)
- M E Corrales
- Departamento de Química Física I (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain
| | - P S Shternin
- Ioffe Institute , Politechnicheskaya 26, 194021 St. Petersburg, Russia
| | - L Rubio-Lago
- Departamento de Química Física I (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain
| | - R de Nalda
- Instituto de Química Física Rocasolano, CSIC , C/Serrano 119, 28006 Madrid, Spain
| | - O S Vasyutinskii
- Ioffe Institute , Politechnicheskaya 26, 194021 St. Petersburg, Russia
| | - L Bañares
- Departamento de Química Física I (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain
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9
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Photodissociation dynamics of iodocyclohexane upon UV excitation by femtosecond pump–probe technique. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.06.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Liu ZM, Wang YM, Hu CL, Long JY, Zhang B. Photodissociation Dynamics of 2-Iodotoluene Investigated by Femtosecond Time-Resolved Mass Spectrometry. CHINESE J CHEM PHYS 2016. [DOI: 10.1063/1674-0068/29/cjcp1512243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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11
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Balerdi G, Woodhouse J, Zanchet A, de Nalda R, Senent ML, García-Vela A, Bañares L. Femtosecond predissociation dynamics of the methyl radical from the 3pz Rydberg state. Phys Chem Chem Phys 2016; 18:110-8. [DOI: 10.1039/c5cp05710h] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vibrationally state selected predissociation lifetimes for the methyl radical in the 3pz Rydberg state have been measured by femtosecond velocity map imaging and the results explained by ab initio theoretical calculations.
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Affiliation(s)
- Garikoitz Balerdi
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid (Unidad Asociada I+D+i CSIC)
- 28040 Madrid
- Spain
| | - Joanne Woodhouse
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid (Unidad Asociada I+D+i CSIC)
- 28040 Madrid
- Spain
| | | | | | - María L. Senent
- Departamento de Química y Física Teóricas
- Instituto de Estructura de la Materia
- CSIC
- Madrid 28006
- Spain
| | | | - Luis Bañares
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid (Unidad Asociada I+D+i CSIC)
- 28040 Madrid
- Spain
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12
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Xu H, Pratt ST. Photodissociation of Methyl Iodide via Selected Vibrational Levels of the B̃ ((2)E3/2)6s Rydberg State. J Phys Chem A 2015; 119:7548-58. [PMID: 25946320 DOI: 10.1021/acs.jpca.5b00860] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have determined the I (2)P3/2 and (2)P1/2 branching fractions following the photodissociation of methyl iodide (CH3I) via a number of vibronic bands associated with the B̃ ((2)E3/2)6s Rydberg state at excitation wavelengths between 201.2 and 192.7 nm. Vacuum ultraviolet light at 118.2 nm was used to ionize both the product iodine atoms and the methyl radical cofragments, and velocity map ion imaging was used to determine the product translational energy distributions and angular distributions. The known relative photoionization cross sections for I (2)P3/2 and (2)P1/2 at 118.2 nm were used to determine the corresponding branching fractions. The results extend our earlier work at 193 nm by Xu et al. (J. Chem. Phys. 2013, 139, 214310), and complement the closely related work of González et al. (J. Chem. Phys. 2011, 135, 021102). We find that for most of the excited vibronic levels of the B̃ state studied, the I (2)P3/2 branching ratio is small, but nonzero, and that this channel is associated with internally excited CH3 radicals. The results are discussed in relation to the recent theoretical results of Alekseyev et al. (J. Chem. Phys. 2011, 134, 044303).
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Affiliation(s)
- Hong Xu
- Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - S T Pratt
- Argonne National Laboratory, Argonne, Illinois 60439, United States
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13
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Marggi Poullain S, González MG, Samartzis PC, Kitsopoulos TN, Rubio-Lago L, Bañares L. New insights into the photodissociation of methyl iodide at 193 nm: stereodynamics and product branching ratios. Phys Chem Chem Phys 2015; 17:29958-68. [DOI: 10.1039/c5cp04850h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Stereodynamics imaging provides new insights into the photodissociation of methyl iodide at 193 nm.
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Affiliation(s)
- Sonia Marggi Poullain
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Marta G. González
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Peter C. Samartzis
- Institute of Electronic Structure and Laser (IESL)
- Foundation for Research and Technology-Hellas (FORTH)
- Heraklion
- Greece
| | - Theofanis N. Kitsopoulos
- Institute of Electronic Structure and Laser (IESL)
- Foundation for Research and Technology-Hellas (FORTH)
- Heraklion
- Greece
- Department of Chemistry
| | - Luis Rubio-Lago
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Luis Bañares
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
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14
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González MG, Rodríguez JD, Rubio-Lago L, Bañares L. Imaging the stereodynamics of methyl iodide photodissociation in the second absorption band: fragment polarization and the interplay between direct and predissociation. Phys Chem Chem Phys 2014; 16:26330-41. [DOI: 10.1039/c4cp03823a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Stereodynamics imaging disentangles the interplay between direct and predissociation in the onset of the second absorption band of methyl iodide.
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Affiliation(s)
- Marta G. González
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid, Spain
| | - Javier D. Rodríguez
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid, Spain
| | - Luis Rubio-Lago
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid, Spain
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15
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Donovan RJ, Hennessy JT, Lawley KP, Ridley T. A critical re-assignment of the Rydberg states of iodomethane based on new polarization data. J Chem Phys 2013; 138:134308. [DOI: 10.1063/1.4798972] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Corrales ME, Balerdi G, Loriot V, de Nalda R, Bañares L. Strong field control of predissociation dynamics. Faraday Discuss 2013; 163:447-60; discussion 513-43. [DOI: 10.1039/c2fd20143g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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17
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Zhao W, Wang W, Qu P, Hou K, Li H. Multiple ionization of CH3I clusters by nanosecond laser: Electron energy distribution and formation mechanism of multiply charged ions. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.06.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Photofragment angular momentum polarization in the photolysis of symmetric top molecules: Production, detection, and rotational depolarization. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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19
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Gitzinger G, Corrales ME, Loriot V, de Nalda R, Bañares L. A femtosecond velocity map imaging study on B-band predissociation in CH3I. II. The 201 and 301 vibronic levels. J Chem Phys 2012; 136:074303. [DOI: 10.1063/1.3683252] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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García-Vela A, de Nalda R, Durá J, González-Vázquez J, Bañares L. A 4D wave packet study of the CH3I photodissociation in the A-band. Comparison with femtosecond velocity map imaging experiments. J Chem Phys 2012; 135:154306. [PMID: 22029312 DOI: 10.1063/1.3650718] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The time-resolved photodissociation dynamics of CH(3)I in the A-band has been studied theoretically using a wave packet model including four degrees of freedom, namely the C-I dissociation coordinate, the I-CH(3) bending mode, the CH(3) umbrella mode, and the C-H symmetric stretch mode. Clocking times and final product state distributions of the different dissociation (nonadiabatic) channels yielding spin-orbit ground and excited states of the I fragment and vibrationless and vibrationally excited (symmetric stretch ν(1) and umbrella ν(2) modes) CH(3) fragments have been obtained and compared with the results of femtosecond velocity map imaging experiments. The wave packet calculations are able to reproduce with very good agreement the experimental reaction times for the CH(3)(ν(1), ν(2))+I*((2)P(1/2)) dissociation channels with ν(1) = 0 and ν(2) = 0,1,2, and also for the channel CH(3)(ν(1) = 0, ν(2) = 0)+I((2)P(3/2)). However, the model fails to predict the experimental clocking times for the CH(3)(ν(1), ν(2))+I((2)P(3/2)) channels with (ν(1), ν(2)) = (0, 1), (0, 2), and (1, 0), that is, when the CH(3) fragment produced along with spin-orbit ground state I atoms is vibrationally excited. These results are similar to those previously obtained with a three-dimensional wave packet model, whose validity is discussed in the light of the results of the four-dimensional treatment. Possible explanations for the disagreements found between theory and experiment are also discussed.
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Affiliation(s)
- A García-Vela
- Instituto de Física Fundamental, CSIC, C/ Serrano, 123, 28006 Madrid, Spain.
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21
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Corrales ME, Gitzinger G, González-Vázquez J, Loriot V, de Nalda R, Bañares L. Velocity Map Imaging and Theoretical Study of the Coulomb Explosion of CH3I under Intense Femtosecond IR Pulses. J Phys Chem A 2011; 116:2669-77. [DOI: 10.1021/jp207367a] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- María E. Corrales
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Gregory Gitzinger
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Instituto de Química Física Rosacolano, CSIC, C/Serrano 119, 28006 Madrid, Spain
| | - Jesús González-Vázquez
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Instituto de Química Física Rosacolano, CSIC, C/Serrano 119, 28006 Madrid, Spain
| | - Vincent Loriot
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Instituto de Química Física Rosacolano, CSIC, C/Serrano 119, 28006 Madrid, Spain
| | - Rebeca de Nalda
- Instituto de Química Física Rosacolano, CSIC, C/Serrano 119, 28006 Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
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González MG, Rodríguez JD, Rubio-Lago L, Bañares L. Communication: First observation of ground state I(2P3/2) atoms from the CH3I photodissociation in the B-band. J Chem Phys 2011; 135:021102. [DOI: 10.1063/1.3613656] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Alekseyev AB, Liebermann HP, Buenker RJ. Ab initioconfiguration interaction study of theB- andC-band photodissociation of methyl iodide. J Chem Phys 2011; 134:044303. [DOI: 10.1063/1.3532926] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Thiré N, Cireasa R, Staedter D, Blanchet V, Pratt ST. Time-resolved predissociation of the vibrationless level of the B state of CH3I. Phys Chem Chem Phys 2011; 13:18485-96. [DOI: 10.1039/c1cp22057h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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