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Weike N, Eisfeld W, Dunseath KM, Viel A. Hydrogen-iodine scattering. II. Rovibronic analysis and collisional dynamics. J Chem Phys 2024; 161:014302. [PMID: 38953441 DOI: 10.1063/5.0219156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Accepted: 06/06/2024] [Indexed: 07/04/2024] Open
Abstract
Our recently published [Weike et al., J. Chem. Phys. 159, 244119 (2023)] spin-orbit coupled diabatic potential energy model for HI is used in a thorough analysis of bound and quasi-bound states as well as elastic and inelastic processes in H + I collisions. The potential energy model, designed explicitly for studying scattering, accurately describes the various couplings in the system, which lead to complex dynamics. Ro-vibronic bound and quasi-bound states related to the adiabatic electronic ground state and an excited electronic state are analyzed. Calculations using the full 104 × 104 diabatic matrix model or a single adiabatic state are compared in order to investigate approximations in the latter. Elastic and inelastic scattering cross sections as well as thermal rates between the ground and first excited fine structure levels of iodine are computed for collision energies up to 12 500 cm-1. Resonances related to the quasi-bound states are analyzed in terms of their energy, width, lifetime, and decay probabilities. The effect of different resonances on the thermal rates is discussed. Resonances between 30 000 and 40 000 cm-1 are also studied for selected values of the total angular momentum, in particular their decay probabilities into different final states of iodine and hence their potential effect on branching ratios in photodissociation of HI.
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Affiliation(s)
- Nicole Weike
- Theoretische Chemie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
| | - Wolfgang Eisfeld
- Theoretische Chemie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
| | - Kevin M Dunseath
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, F-35000 Rennes, France
| | - Alexandra Viel
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, F-35000 Rennes, France
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Weike N, Viel A, Eisfeld W. Hydrogen-iodine scattering. I. Development of an accurate spin-orbit coupled diabatic potential energy model. J Chem Phys 2023; 159:244119. [PMID: 38156638 DOI: 10.1063/5.0186787] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 12/05/2023] [Indexed: 01/03/2024] Open
Abstract
The scattering of H by I is a prototypical model system for light-heavy scattering in which relativistic coupling effects must be taken into account. Scattering calculations depend strongly on the accuracy of the potential energy surface (PES) model. The methodology to obtain such an accurate PES model suitable for scattering calculations is presented, which includes spin-orbit (SO) coupling within the Effective Relativistic Coupling by Asymptotic Representation (ERCAR) approach. In this approach, the SO coupling is determined only for the atomic states of the heavy atom, and the geometry dependence of the SO effect is accounted for by a diabatization with respect to asymptotic states. The accuracy of the full model, composed of a Coulomb part and the SO model, is achieved in the following ways. For the SO model, the extended ERCAR approach is applied, which accounts for both intra-state and inter-state SO coupling, and an extended number of diabatic states are included. The corresponding coupling constants for the SO operator are obtained from experiments, which are more accurate than computed values. In the Coulomb Hamiltonian model, special attention is paid to the long range behavior and accurate c6 dispersion coefficients. The flexibility and accuracy of this Coulomb model are achieved by combining partial models for three different regions. These are merged via artificial neural networks, which also refine the model further. In this way, an extremely accurate PES model for hydrogen iodide is obtained, suitable for accurate scattering calculations.
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Affiliation(s)
- Nicole Weike
- Theoretische Chemie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
| | - Alexandra Viel
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, F-35000 Rennes, France
| | - Wolfgang Eisfeld
- Theoretische Chemie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
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3
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Todt MA, Datta S, Rose A, Leung K, Davis HF. Subpicosecond HI elimination in the 266 nm photodissociation of branched iodoalkanes. Phys Chem Chem Phys 2020; 22:27338-27347. [DOI: 10.1039/c9cp06460e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New experiments reveal a close connection between the nonadiabatic dynamics of C–I bond fission and HI elimination in the photodissociation of branched iodoalkanes.
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Affiliation(s)
- Michael A. Todt
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
| | - Sagnik Datta
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
| | - Alex Rose
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
| | - Kiana Leung
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
| | - H. Floyd Davis
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
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Hilsabeck KI, Meiser JL, Sneha M, Balakrishnan N, Zare RN. Photon catalysis of deuterium iodide photodissociation. Phys Chem Chem Phys 2019; 21:14195-14204. [DOI: 10.1039/c8cp06107f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photodissociation of deuterium iodide is catalyzed by the electric field supplied by nonresonant IR photons.
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Affiliation(s)
| | | | - Mahima Sneha
- Department of Chemistry
- Stanford University
- Stanford
- USA
| | - N. Balakrishnan
- Department of Chemistry and Biochemistry
- University of Nevada
- Las Vegas
- USA
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5
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Alekseyev AB, Liebermann HP, Vázquez GJ, Lefebvre-Brion H. Coupled-channel study of the Rydberg–valence interaction in HBr. J Chem Phys 2018; 148:084302. [DOI: 10.1063/1.5018167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. B. Alekseyev
- Fakultät für Mathematik und Naturwissenschaften, Physikalische und Theoretische Chemie, Bergische Universität Wuppertal, Gaußstraße 20, D-42097 Wuppertal, Germany
| | - H.-P. Liebermann
- Fakultät für Mathematik und Naturwissenschaften, Physikalische und Theoretische Chemie, Bergische Universität Wuppertal, Gaußstraße 20, D-42097 Wuppertal, Germany
| | - G. J. Vázquez
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (UNAM), 62210 Cuernavaca, Mexico
| | - H. Lefebvre-Brion
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Université Paris-Saclay, 91405 Orsay Cedex, France
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6
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Leplat N, Wokaun A, Rossi MJ. Reinvestigation of the Elementary Chemical Kinetics of the Reaction C2H5• + HBr (HI) → C2H6 + Br• (I•) in the Range 293–623 K and Its Implication on the Thermochemical Parameters of C2H5• Free Radical. J Phys Chem A 2013; 117:11383-402. [DOI: 10.1021/jp403761r] [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)
- N. Leplat
- Laboratory
of Atmospheric Chemistry (LAC) and ‡General Energy Research (ENE) Division, Paul Scherrer Institute (PSI), CH-5232 Villigen PSI, Switzerland
| | - A. Wokaun
- Laboratory
of Atmospheric Chemistry (LAC) and ‡General Energy Research (ENE) Division, Paul Scherrer Institute (PSI), CH-5232 Villigen PSI, Switzerland
| | - M. J. Rossi
- Laboratory
of Atmospheric Chemistry (LAC) and ‡General Energy Research (ENE) Division, Paul Scherrer Institute (PSI), CH-5232 Villigen PSI, Switzerland
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7
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Alekseyev AB, Liebermann HP, Buenker RJ. Potential energy surfaces for ground and excited electronic states of the CF3I molecule and their relevance to its A-band photodissociation. Phys Chem Chem Phys 2013; 15:6660-6. [DOI: 10.1039/c3cp44237c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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8
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Campbell EK, Alekseyev AB, Balint-Kurti GG, Brouard M, Brown A, Buenker RJ, Johnsen AJ, Kokh DB, Lucas S, Winter B. The vibrationally mediated photodissociation of Cl2. J Chem Phys 2012; 137:124310. [PMID: 23020334 DOI: 10.1063/1.4754160] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photodissociation of vibrationally excited Cl(2)(v = 1) has been investigated experimentally using the velocity mapped ion imaging technique. The experimental measurements presented here are compared with the results of time-dependent wavepacket calculations performed on a set of ab initio potential energy curves. The high level calculations allow prediction of all the dynamical information regarding the dissociation, including electronic polarization effects. Using a combination of theory and experiment it was found that there was negligible cooling of the vibrational degree of freedom of the parent molecule in the molecular beam. The results presented are compared with those following the photodissociation of Cl(2)(v = 0). Although the same electronic states are found to be important for Cl(2)(v = 1) as for Cl(2)(v = 0), significant differences were found regarding many of the observables. The overall level of agreement between theory and experiment was found to be reasonable and confirms previous assignments of the photodissociation mechanism.
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Affiliation(s)
- E K Campbell
- The Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
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9
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Ndome H, Eisfeld W. Spin-orbit coupled potential energy surfaces and properties using effective relativistic coupling by asymptotic representation. J Chem Phys 2012; 137:064101. [DOI: 10.1063/1.4740248] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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FUJISAKI HIROSHI, TERANISHI YOSHIAKI, NAKAMURA HIROKI. CONTROL OF PHOTODISSOCIATION BRANCHING USING THE COMPLETE REFLECTION PHENOMENON: APPLICATION TO HI MOLECULE. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2012. [DOI: 10.1142/s0219633602000269] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The laser control of photodissociation branching in a diatomic molecule is demonstrated to be effectively achieved with use of the complete reflection phenomenon. The phenomenon and the control condition can be nicely formulated by the semiclassical (Zhu–Nakamura) theory. The method is applied to the branching between I (2P3/2) ( HI → H + I ) and I *(2P1/2) ( HI → H + I *) formation, and nearly complete control is shown to be possible by appropriately choosing an initial vibrational state and laser frequency in spite of the fact that there are three electronically excited states involved. Numerical calculations of the corresponding wavepacket dynamics confirm the results.
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Affiliation(s)
- HIROSHI FUJISAKI
- Department of Theoretical Studies, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan
| | - YOSHIAKI TERANISHI
- Advanced Photon Research Center, Japan Atomic Energy Research Institute, Kizu-cho, Kyoto 619-0215, Japan
| | - HIROKI NAKAMURA
- Department of Theoretical Studies, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan
- Department of Functional Molecular Science, The Graduate University for Advanced Studies, Myodaiji, Okazaki 444-8585, Japan
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11
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Ndome H, Welsch R, Eisfeld W. A new method to generate spin-orbit coupled potential energy surfaces: Effective relativistic coupling by asymptotic representation. J Chem Phys 2012; 136:034103. [DOI: 10.1063/1.3675846] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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12
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Preller M, Grunenberg J, Bulychev VP, Bulanin MO. Calculation of the structure, potential energy surface, vibrational dynamics, and electric dipole properties for the Xe:HI van der Waals complex. J Chem Phys 2011; 134:174302. [DOI: 10.1063/1.3583817] [Citation(s) in RCA: 6] [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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13
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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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14
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Sage AG, Oliver TAA, Murdock D, Crow MB, Ritchie GAD, Harvey JN, Ashfold MNR. nσ* and πσ* excited states in aryl halide photochemistry: a comprehensive study of the UV photodissociation dynamics of iodobenzene. Phys Chem Chem Phys 2011; 13:8075-93. [DOI: 10.1039/c0cp02390f] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Poterya V, Fedor J, Pysanenko A, Tkáč O, Lengyel J, Ončák M, Slavíček P, Fárník M. Photochemistry of HI on argon and waternanoparticles: Hydronium radical generation in HI·(H2O)n. Phys Chem Chem Phys 2011; 13:2250-8. [DOI: 10.1039/c0cp01518k] [Citation(s) in RCA: 19] [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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16
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17
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Zhao Y, Tong C, Ma L. Assessment of a novel flow visualization technique using photodissociation spectroscopy. APPLIED SPECTROSCOPY 2009; 63:199-206. [PMID: 19215650 DOI: 10.1366/000370209787392021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The study of complicated flows continuously calls for new nonintrusive flow diagnostics. A novel flow visualization technique based on photodissociation spectroscopy (PDS) is described, demonstrated, and assessed in this paper. This technique is centered around the creative use of photodissociation (PD). A PD precursor is seeded in the flow of interest, either passive or reactive. A laser pulse is then generated to completely and rapidly photodissociate both the precursor and the products formed from the precursor (if it reacts) into photofragments. A target photofragment is then imaged to obtain multidimensional information about the flow. An analytical methodology was developed to assess the feasibility of the PDS-based technique. This analytical method was applied to the case where molecular iodine was used as an example PD precursor, and the results were validated by experimental data. Both the analytical and experimental findings provided a promising outlook for this new technique as a practical flow visualization technique. With a properly chosen PD precursor, the PDS-based technique provides an attractive alternative for imaging several critical flow properties, including the mixture fraction and temperature field. This technique shares some key advantages with established techniques, e.g., a high spatial and temporal resolution comparable to the planar laser-induced fluorescence (PLIF) technique. Meanwhile, this technique offers several unique advantages to overcome the limitations of existing techniques, including enhancing the signal level and simplifying the interpretation of the signal.
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Affiliation(s)
- Yan Zhao
- Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634-0921, USA
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18
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Alekseyev AB, Liebermann HP, Buenker RJ. On the ultraviolet photofragmentation of CH3Xe+. J Chem Phys 2009; 130:024309. [DOI: 10.1063/1.3055909] [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] Open
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19
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Alekseyev AB, Liebermann HP, Buenker RJ. Spin-orbit configuration interaction study of the ultraviolet photofragmentation of XeH+. Phys Chem Chem Phys 2008; 10:5706-13. [PMID: 18956105 DOI: 10.1039/b807078d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The multireference spin-orbit CI method is employed to calculate potential energy curves for the ground and low-lying excited states of the XeH+ cation. For the first time, the spin-orbit interaction is taken into account and electric dipole moments are computed for transitions to the states responsible for the first absorption continuum (A band) of XeH+. On this basis, the partial and total absorption spectra in this energy range are obtained. It is found that the A-band absorption is dominated by the spin-forbidden b3Pi0+ <-- X1sigma+ parallel transition, while perpendicular transitions to the B(1)Pi and b(3)Pi(1) states are significantly weaker. The Gamma(nu) branching ratio defined as the ratio of the Xe+(2P(1/2)) yield to the total yield of the Xe+ cations from the XeH+ photodissociation is calculated for the (42-80) x 10(3) spectral range. It is shown that Gamma(nu) increases smoothly from <0.2 in the red and blue tails of the band to its maximum of 0.92 in the middle of the band, at E approximately 51.4 x 10(3) cm(-1). The high Gamma(nu) values correspond to the predominant formation of the spin-excited Xe+(2P(1/2)) ions that may be used to obtain IR laser generation at the Xe+(2P(1/2) - 2P(3/2)) transition. The calculated XeH+ data are compared with those for the isovalent ArH+, KrH+, and HI systems.
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Affiliation(s)
- Aleksey B Alekseyev
- Fachbereich C, Theoretische Chemie, Bergische Universität Wuppertal, Wuppertal, Germany.
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20
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Suits AG, Vasyutinskii OS. Imaging Atomic Orbital Polarization in Photodissociation. Chem Rev 2008; 108:3706-46. [DOI: 10.1021/cr040085c] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Arthur G. Suits
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, and Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Oleg S. Vasyutinskii
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, and Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
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21
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Alekseyev AB, Buenker RJ, Liebermann HP. Ab initiostudy of the KrH+ photodissociation. J Chem Phys 2008; 128:234308. [DOI: 10.1063/1.2939250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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22
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Valero R, Truhlar DG, Jasper AW. Adiabatic States Derived from a Spin-Coupled Diabatic Transformation: Semiclassical Trajectory Study of Photodissociation of HBr and the Construction of Potential Curves for LiBr+. J Phys Chem A 2008; 112:5756-69. [DOI: 10.1021/jp800738b] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rosendo Valero
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431
| | - Donald G. Truhlar
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431
| | - Ahren W. Jasper
- Combustion Research Facility, Sandia National Laboratories, P. O. Box 969, Livermore, California 94551-0969
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Nonadiabatic Chemical Dynamics: Comprehension and Control of Dynamics, and Manifestation of Molecular Functions. ADVANCES IN CHEMICAL PHYSICS 2008. [DOI: 10.1002/9780470259474.ch3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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24
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López-López S, Prosmiti R, García-Vela A. Effect of the Excitation Energy on the (HI)2 Nonadiabatic Photodissociation Dynamics. J Phys Chem A 2008; 112:2762-72. [DOI: 10.1021/jp710696e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. López-López
- Instituto de Matematicas y Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
| | - R. Prosmiti
- Instituto de Matematicas y Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
| | - A. García-Vela
- Instituto de Matematicas y Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
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25
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López-López S, Prosmiti R, García-Vela A. Modeling the (HI)2 photodissociation dynamics through a nonadiabatic wave packet study of the I*–HI complex. J Chem Phys 2007; 127:184307. [DOI: 10.1063/1.2803898] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Wang F, Lu IC, Yuan K, Cheng Y, Wu M, Parker DH, Yang X. Photodissociation dynamics of HI and DI at 157nm. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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27
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Alekseyev AB, Liebermann HP, Buenker RJ. Theoretical study of the ArH+ photodissociation. Phys Chem Chem Phys 2007; 9:5088-95. [PMID: 17878984 DOI: 10.1039/b706670h] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The multireference Spin-Orbit (SO) Configuration Interaction (CI) method in its Lambda-S Contracted SO-CI (LSC-SO-CI) version is employed to calculate potential energy curves for the ground and low-lying excited states of the ArH(+) cation. For the first time, electric dipole moments are also computed in the approach, including SO coupling for transitions to the states responsible for the first absorption continuum (A-band) of ArH(+). On this basis, the partial and total absorption spectra in this energy range are obtained. It is shown that absorption in the A-band is dominated by the parallel A(1)Sigma(+)<--X(1)Sigma(+) transition. In the low-energy part of the band (<95 x 10(3) cm(-1)) the absorption is caused by the perpendicular B(1)Pi<--X(1)Sigma(+) excitation, but transitions to the b(3)Pi(0(+),1) states are also not negligible. The branching ratio Gamma for the final photodissociation products is calculated and it is shown to increase smoothly from 0 in the red tail of the band to 1 at E>or= 10(5) cm(-1). The latter value corresponds to the exclusive formation of the spin-excited Ar(+)((2)P(1/2)) ions, and thus leads to the inverse population of the Ar(+)((2)P(1/2)-(2)P(3/2)) ion states.
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Affiliation(s)
- Aleksey B Alekseyev
- Fachbereich C-Theoretische Chemie, Bergische Universität Wuppertal, Germany.
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28
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Alekseyev AB, Liebermann HP, Buenker RJ. Anab initiostudy of the CH3I photodissociation. II. Transition moments and vibrational state control of the I* quantum yields. J Chem Phys 2007; 126:234103. [PMID: 17600400 DOI: 10.1063/1.2736696] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Multireference spin-orbit configuration interaction calculations of transition moments from the X A1 ground state to the 3Q0+, 3Q1, and 1Q excited states responsible for the A absorption band of CH3I are reported and employed for an analysis of the photofragmentation in this system. Contrary to what is usually assumed, the 3Q0+(A1), 3Q1(E), and 1Q(E)<--X A1 transition moments are found to be strongly dependent on the C-I fragmentation coordinate. The sign of this dependence is opposite for the parallel and perpendicular transitions, which opens an opportunity for vibrational state control of the photodissociation product yields. The computed absorption intensity distribution and the I* quantum yield as a function of excitation energy are analyzed in comparison with existing experimental data, and good agreement between theory and experiment is found. It is predicted that significantly higher I* quantum yield values (>0.9) may be achieved when vibrationally hot CH3I molecules are excited in the appropriate spectral range. It is shown that vibrational state control of the I*/I branching ratio in the alkyl (hydrogen) iodide photodissociation has an electronic rather than a dynamic nature: Due to a different electron density distribution at various molecular geometries, one achieves a more efficient excitation of a particular fragmentation channel rather than influences the dynamics of the decay process.
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Affiliation(s)
- Aleksey B Alekseyev
- Fachbereich C-Theoretische Chemie, Bergische Universität Wuppertal, Gaussstr. 20, D-42097 Wuppertal, Germany.
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29
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Alekseyev AB, Liebermann HP, Buenker RJ, Yurchenko SN. Anab initiostudy of the CH3I photodissociation. I. Potential energy surfaces. J Chem Phys 2007; 126:234102. [PMID: 17600399 DOI: 10.1063/1.2736695] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The multireference spin-orbit (SO) configuration interaction (CI) method in its Lambda-S contracted SO-CI version is employed to calculate two-dimensional potential energy surfaces for the ground and low-lying excited states of CH3I relevant to the photodissociation process in its A absorption band. The computed equilibrium geometry for the X A1 ground state, as well as vibrational frequencies for the nu2 umbrella and nu3 symmetric stretch modes, are found to be in good agreement with available experimental data. The 3Q0+ state converging to the excited I(2P1/2o) limit is found to possess a shallow minimum of 850 cm(-1) strongly shifted to larger internuclear distances (RC-I approximately 6.5a0) relative to the ground state. This makes a commonly employed single-exponent approximation for analysis of the CH3I fragmentation dynamics unsuitable. The 4E(3A1) state dissociating to the same atomic limit is calculated to lie too high in the Franck-Condon region to have any significant impact on the A-band absorption. The computed vertical excitation energies for the 3Q1, 3Q0+, and 1Q states indicate that the A-band spectrum must lie approximately between 33,000 and 44,300 cm(-1), i.e., between 225 and 300 nm. This result is in very good agreement with the experimental findings. The lowest Rydberg states are computed to lie at >or=49,000 cm(-1) and correspond to the ...a(1)2n3a1(6sI) leading configuration. They are responsible for the vacuum ultraviolet absorption lines found experimentally beyond the A-band spectrum at 201.1 nm (49,722 cm(-1)) and higher.
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Affiliation(s)
- Aleksey B Alekseyev
- Fachbereich C-Theoretische Chemie, Bergische Universität Wuppertal, Gaussstr. 20, D-42097 Wuppertal, Germany.
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30
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Bi W, Xu X, Huang J, Xiao D, Tang Z, Zhu Q. Study on the (HI)
m
(H 2O)
n
Clusters by Photofragment Translational Spectroscopy and Ab-Initio Calculation. Z PHYS CHEM 2007. [DOI: 10.1524/zpch.2007.221.6.815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The photodissociation of the clusters (HI)
m
(H2O)
n
in the supersonic molecular beam has been investigated at 281.73 nm and 280.99 nm by photofragment translational spectroscopy (PTS). The translational energy distributions of the photofragment I*(2
P
1/2) show that the photodissociated species is mainly HI(H2O)
n
(n ≥ 4) clusters. In addition, the structures and the relative stability of (HI)
m
, (H2O)
n
and (HI)
m
(H2O)
n
(m = 1 ∼ 4, n = 1 ∼ 6) clusters have been obtained by ab initio calculation (the Density Functional Theory). The conclusion of the theoretical analysis is agreeable with the experimental results. So these results indicate that PTS combining theoretical calculation can be used as a new, indirect way to judge the composition of the clusters which are easy to be dissociated and difficult to be detected by mass spectroscopy.
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31
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López-López S, Prosmiti R, García-Vela A. Nonadiabatic photodissociation dynamics in (HI)2 induced by intracluster collisions. J Chem Phys 2007; 126:161102. [PMID: 17477581 DOI: 10.1063/1.2731371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The sequential photodissociation dynamics of (HI)2 is studied by means of a nonadiabatic wave packet treatment starting from the I*-HI complex. The model reproduces the main experimental findings for photolysis with 266 nm radiation. The results confirm that some of the H atoms dissociated from the I*-HI complex deactivate the I* atom through a HI* intracluster collision which induces an I*-->I electronically nonadiabatic transition. As a consequence, these H fragments become very fast by acquiring nearly all the I* excitation energy, equivalent to the I*I spin-orbit splitting. A most interesting result is the high production of bound I2 fragments in highly excited rovibrational states in the photolysis, indicating that the H dissociation is mainly direct.
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Affiliation(s)
- S López-López
- Instituto de Matemáticas y Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
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32
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Smolin AG, Vasyutinskii OS, Balint-Kurti GG, Brown A. Photodissociation of HBr. 1. Electronic Structure, Photodissociation Dynamics, and Vector Correlation Coefficients. J Phys Chem A 2006; 110:5371-8. [PMID: 16623464 DOI: 10.1021/jp0562429] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ab initio potential energy curves, transition dipole moments, and spin-orbit coupling matrix elements are computed for HBr. These are then used, within the framework of time-dependent quantum-mechanical wave-packet calculations, to study the photodissociation dynamics of the molecule. Total and partial integral cross sections, the branching fraction for the formation of excited-state bromine atoms Br(2P(1/2)), and the lowest order anisotropy parameters, beta, for both ground and excited-state bromine are calculated as a function of photolysis energy and compared to experimental and theoretical data determined previously. Higher order anisotropy parameters are computed for the first time for HBr and compared to recent experimental measurements. A new expression for the Re[a1(3) (parallel, perpendicular)] parameter describing coherent parallel and perpendicular production of ground-state bromine in terms of the dynamical functions is given. Although good agreement is obtained between the theoretical predictions and the experimental measurements, the discrepancies are analyzed to establish how improvements might be achieved. Insight is obtained into the nonadiabatic dynamics by comparing the results of diabatic and fully adiabatic calculations.
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Affiliation(s)
- Andrey G Smolin
- Ioffe Physico-Technical Institute Russian Academy of Sciences, 194021 St.-Petersburg, Russia.
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33
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Clark AP, Brouard M, Quadrini F, Vallance C. Atomic polarization in the photodissociation of diatomic molecules. Phys Chem Chem Phys 2006; 8:5591-610. [PMID: 17149481 DOI: 10.1039/b612590e] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The angular momentum polarization of atomic photofragments provides a detailed insight into the dynamics of the photodissociation process. In this article, the origins of electronic angular momentum polarization are introduced and experimental and theoretical methods for the measurement or calculation of atomic orientation and alignment parameters described. Many diatomic photodissociation systems are surveyed, in order to provide an overview both of the historical development of the field and of the most state-of-the-art contemporary studies.
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Affiliation(s)
- A P Clark
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK
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34
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Underwood J, Chastaing D, Lee S, Wittig C. Heavy hydrides: H2Te ultraviolet photochemistry. J Chem Phys 2005; 123:084312. [PMID: 16164296 DOI: 10.1063/1.2008261] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The room-temperature ultraviolet absorption spectrum of H2Te has been recorded. Unlike other group-6 hydrides, it displays a long-wavelength tail that extends to 400 nm. Dissociation dynamics have been examined at photolysis wavelengths of 266 nm (which lies in the main absorption feature) and 355 nm (which lies in the long-wavelength tail) by using high-n Rydberg time-of-flight spectroscopy to obtain center-of-mass translational energy distributions for the channels that yield H atoms. Photodissociation at 355 nm yields TeH(2Pi1/2) selectively relative to the TeH(2Pi3/2) ground state. This is attributed to the role of the 3A' state, which has a shallow well at large R(H-TeH) and correlates to H+TeH(2Pi1/2). Note that the 2Pi1/2 state is analogous to the 2P1/2 spin-orbit excited state of atomic iodine, which is isoelectronic with TeH. The 3A' state is crossed at large R only by 2A", with which it does not interact. The character of 3A' at large R is influenced by a strong spin-orbit interaction in the TeH product. Namely, 2Pi1/2 has a higher degree of spherical symmetry than does 2Pi3/2 (recall that I(2P1/2) is spherically symmetric), and consequently 2Pi1/2 is not inclined to form either strongly bonding or antibonding orbitals with the H atom. The 3A'<--X transition dipole moment dominates in the long-wavelength region and increases with R. Structure observed in the absorption spectrum in the 380-400 nm region is attributed to vibrations on 3A'. The main absorption feature that is peaked at approximately 240 nm might arise from several excited surfaces. On the basis of the high degree of laboratory system spatial anisotropy of the fragments from 266 nm photolysis, as well as high-level theoretical studies, the main contribution is believed to be due to the 4A" surface. The 4A"<--X transition dipole moment dominates in the Franck-Condon region, and its polarization is in accord with the experimental observations. An extensive secondary photolysis (i.e., of nascent TeH) is observed at 266 and 355 nm, and the corresponding spectral features are assigned. Analyses of the c.m. translational energy distributions yield bond dissociation energies D0. For H2Te and TeH, these are 65.0+/-0.1 and 63.8+/-0.4 kcalmol, respectively, in good agreement with predictions that use high-level relativistic theory.
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Affiliation(s)
- J Underwood
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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35
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Jodoin DN, Brown A. Photodissociation of HI and DI: Testing models for electronic structure via polarization of atomic photofragments. J Chem Phys 2005; 123:054301. [PMID: 16108633 DOI: 10.1063/1.1989327] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photodissociation dynamics of HI and DI are examined using time-dependent wave-packet techniques. The orientation and alignment parameters aQ(K) (p) are determined as a function of photolysis energy for the resulting ground-state I(2P(3/2)) and excited-state I(2P(1/2)) atoms. The aQ(K) (p) parameters describe the coherent and incoherent contributions to the angular momentum distributions from the A 1pi(1), a 3pi(1), and t 3sigma(1) electronic states accessed by perpendicular excitation and the a 3pi(0+) state accessed by a parallel transition. The outcomes of the dynamics based on both shifted ab initio results and three empirical models for the potential-energy curves and transition dipole moments are compared and contrasted. It is demonstrated that experimental measurement of the aQ(K) (p) parameters for the excitation from the vibrational ground state (upsilon=0) would be able to distinguish between the available models for the HI potential-energy curves and transition dipole moments. The differences between the aQ(K) (p) parameters for the excitation from upsilon=0 stand in sharp contrast to the scalar properties, i.e., total cross section and I* branching fraction, which require experimental measurement of photodissociation from excited vibrational states (upsilon>0) to distinguish between the models.
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Affiliation(s)
- David N Jodoin
- Department of Chemistry, University of Alberta, Edmonton AB T6G 2G2, Canada
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36
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Alekseyev AB, Kokh DB, Buenker RJ. HI Photofragmentation Revisited. Comment on “Probing Excited Electronic States Using Vibrationally Mediated Photolysis: Application to Hydrogen Iodide”. J Phys Chem A 2005; 109:3094-6. [PMID: 16833634 DOI: 10.1021/jp044146m] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Aleksey B Alekseyev
- Bergische Universität Wuppertal, Fachbereich C-Theoretische Chemie, Gaussstrasse 20, D-42097 Wuppertal, Germany.
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37
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Brown A. Photodissociation of HI and DI: Polarization of atomic photofragments. J Chem Phys 2005; 122:84301. [PMID: 15836033 DOI: 10.1063/1.1850465] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The complete angular momentum distributions and vector correlation coefficients (orientation and alignment) of ground state I((2)P(32)) and excited state I((2)P(12)) atoms resulting from the photodissociation of HI have been computed as a function of photolysis energy. The orientation and alignment parameters a(Q) ((K))(p) that describe the coherent and incoherent contributions to the angular momentum distributions from the multiple electronic states accessed by parallel and perpendicular transitions are determined using a time-dependent wave packet treatment of the dissociation dynamics. The dynamics are based on potential energy curves and transition dipole moments that have been reported previously [R. J. LeRoy, G. T. Kraemer, and S. Manzhos, J. Chem. Phys. 117, 9353 (2002)] and used to successfully model the scalar (total cross section and branching fraction) and lowest order vector (anisotropy parameter beta) properties of the photodissociation. Predictions of the a(Q) ((K))(p), parameters for the isotopically substituted species DI are reported and contrasted to the analogous HI results. The resulting polarization for the corresponding H/D partners are also determined and demonstrate that both H and D atoms produced can be highly spin polarized. Comparison of these predictions for HI and DI with experimental measurement will provide the most stringent test of the current model for the electronic structure and the interpretation of the dissociation based on noncoupled excited state dynamics.
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Affiliation(s)
- Alex Brown
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
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38
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Alekseyev AB, Liebermann HP, Wittig C. On the ultraviolet photodissociation of H2Te. J Chem Phys 2004; 121:9389-95. [PMID: 15538858 DOI: 10.1063/1.1799572] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photodissociation of H(2)Te through excitation in the first absorption band is investigated by means of multireference spin-orbit configuration interaction (CI) calculations. Bending potentials for low-lying electronic states of H(2)Te are obtained in C(2v) symmetry for Te-H distances fixed at the ground state equilibrium value of 3.14a(0), as well as for the minimum energy path constrained to R(1)=R(2). Asymmetric cuts of potential energy surfaces for excited states (at R(1)=3.14a(0) and theta;=90.3 degrees ) are obtained for the first time. It is shown that vibrational structure in the 380-400 nm region of the long wavelength absorption tail is due to transitions to 3A('), which has a shallow minimum at large HTe-H separations. Transitions to this state are polarized in the molecular plane, and this state converges to the excited TeH((2)Pi(1/2))+H((2)S) limit. These theoretical data are in accord with the selectivity toward TeH((2)Pi(1/2)) relative to TeH((2)Pi(3/2)) that has been found experimentally for 355 nm H(2)Te photodissociation. The calculated 3A(')<--XA(') transition dipole moment increases rapidly with HTe-H distance; this explains the observation of 3A(') vibrational structure for low vibrational levels, despite unfavorable Franck-Condon factors. According to the calculated vertical energies and transition moment data, the maximum in the first absorption band at approximately 245 nm is caused by excitation to 4A("), which has predominantly 2(1)A(") ((1)B(1) in C(2v) symmetry) character.
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Affiliation(s)
- Aleksey B Alekseyev
- Fachbereich C--heoretische Chemie, Bergische Universität Wuppertal, Gaussstrasse 20, D-42097 Wuppertal, Germany.
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39
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López-López S, Prosmiti R, García-Vela A. Quantum treatment of the Ar-HI photodissociation dynamics. J Chem Phys 2004; 121:1802-9. [PMID: 15260731 DOI: 10.1063/1.1767092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A wave packet simulation of the ultraviolet photolysis dynamics of Ar-HI(upsilon = 0) is reported. Cluster photodissociation is started from two different initial states, namely, the ground van der Waals (vdW) and the first excited vdW bending state, associated with the Ar-I-H and Ar-H-I isomeric forms of the system, respectively. Formation of Ar-I radical products is investigated over the energy range of the cluster absorption spectrum. It is found that the yield of bound Ar-I radical complexes is typically 90%-100% and 70%-80% for the initial states associated with the Ar-I-H and Ar-H-I isomers, respectively. This result is in agreement with the experimentally observed time-of-flight spectrum of the hydrogen fragment produced after Ar-HI photodissociation. The high Ar-I yield is explained mainly by the small amount of energy available for the radical that is converted into internal energy in the photofragmentation process, which enhances the Ar-I survival probability. Quantum interference effects manifest themselves in structures in the angular distribution of the hydrogen fragment, and in pronounced rainbow patterns in the rotational distributions of the Ar-I radical.
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Affiliation(s)
- Sergio López-López
- Instituto de Matemáticas y Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain.
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40
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Kokh DB, Alekseyev AB, Buenker RJ. Theoretical study of the UV photodissociation of Cl2: Potentials, transition moments, extinction coefficients, and Cl*/Cl branching ratio. J Chem Phys 2004; 120:11549-56. [PMID: 15268189 DOI: 10.1063/1.1753554] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Potential energy curves for the X (1)Sigma(g) (+) ground state and Omega=0(u) (+), 1(u) valence states and dipole moments for the 0(u) (+), 1(u)-X transitions are obtained in an ab initio configuration interaction study of Cl(2) including spin-orbit coupling. In contrast to common assumptions, it is found that the B (3)Pi(0(+)u)-X transition moment strongly depends on internuclear distance, which has an important influence on the Cl(2) photodissociation. Computed energy curves and transition moments are employed to calculate the A, B, C<--X extinction coefficients, the total spectrum for the first absorption band, and the Cl(*)((2)P(1/2))/Cl((2)P(3/2)) branching ratio as a function of excitation wavelength. The calculated data are shown to be in good agreement with available experimental results.
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Affiliation(s)
- Daria B Kokh
- Bergische Universitat Wuppertal, Fachbereich C-Theoretische Chemie, Gaussstrasse 20, D-42097 Wuppertal, Germany.
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41
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Camden JP, Bechtel HA, Ankeny Brown DJ, Pomerantz AE, Zare RN, Le Roy RJ. Probing Excited Electronic States Using Vibrationally Mediated Photolysis: Application to Hydrogen Iodide. J Phys Chem A 2004. [DOI: 10.1021/jp049051z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Jon P. Camden
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - Hans A. Bechtel
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | | | - Andrew E. Pomerantz
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - Richard N. Zare
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - Robert J. Le Roy
- Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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42
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Brown A, Balint-Kurti GG, Vasyutinskii OS. Photodissociation of HCl and DCl: Polarization of Atomic Photofragments. J Phys Chem A 2004. [DOI: 10.1021/jp0497615] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alex Brown
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - G. G. Balint-Kurti
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - O. S. Vasyutinskii
- Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
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43
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Slavicek P, Jungwirth P, Lewerenz M, Nahler NH, Farnik M, Buck U. Photodissociation of hydrogen iodide on the surface of large argon clusters: The orientation of the librational wave function and the scattering from the cluster cage. J Chem Phys 2004; 120:4498-511. [PMID: 15268618 DOI: 10.1063/1.1643895] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A set of photodissociation experiments and simulations of hydrogen iodide (HI) on Arn clusters, with an average size n = 139, has been carried out for different laser polarizations. The doped clusters are prepared by a pick-up process. The HI molecule is then photodissociated by a UV laser pulse and the outgoing H fragment is ionized by resonance enhanced multiphoton ionization in a (2 + 1) excitation scheme within the same laser pulse at the wavelength of 243 nm. The measured time-of-flight spectra are transformed into hydrogen kinetic energy distributions. They exhibit a strong fraction of caged H atoms at zero-kinetic energy and peaks at the unperturbed cage exit for both spin-orbit channels nearly independent of the polarization. At this dissociation wavelength, the bare HI molecule exhibits a strict state separation, with a parallel transition to the spin-orbit excited state and perpendicular transitions to the ground state. The experimental results have been reproduced using molecular simulation techniques. Classical molecular dynamics was used to estimate the HI dopant distribution after the pick-up procedure. Subsequently, quasi-classical molecular dynamics (Wigner trajectories approach) has been applied for the photodissociation dynamics. The following main results have been obtained: (i) The HI dopant lands on the surface of the argon cluster during the pick-up process, (ii) zero-point energy plays a dominant role for the hydrogen orientation in the ground state of HI-Arn surface clusters, qualitatively changing the result of the photodissociation experiment upon increasing the number of argon atoms, and, finally, (iii) the scattering of hydrogen atoms from the cage which originate from different dissociation states seriously affects the experimentally measured kinetic energy distributions.
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Affiliation(s)
- Petr Slavicek
- J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Center for Complex Molecular Systems and Biomolecules, Dolejskova 3, 18223 Prague 8, Czech Republic
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44
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Yencha AJ, Baltzer P, Cormack AJ, Li Y, Liebermann HP, Alekseyev AB, Buenker RJ. High-resolution photoelectron spectroscopy of HI and DI: Experimental and theoretical analysis of the A 2Σ+ ion system. J Chem Phys 2003. [DOI: 10.1063/1.1603735] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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45
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Chastaing D, Underwood J, Wittig C. Intracluster superelastic scattering via sequential photodissociation in small HI clusters. J Chem Phys 2003. [DOI: 10.1063/1.1574014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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46
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Le Roy RJ, Kraemer GT, Manzhos S. 1 potential, 2 potentials, 3 potentials–4: Untangling the UV photodissociation spectra of HI and DI. J Chem Phys 2002. [DOI: 10.1063/1.1513303] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Manzhos S, Loock HP, Bakker BLG, Parker DH. Photodissociation of hydrogen iodide in the A-band region 273–288 nm. J Chem Phys 2002. [DOI: 10.1063/1.1513250] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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48
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Buck U. Photodissociation of Hydrogen Halide Molecules in Different Cluster Environments. J Phys Chem A 2002. [DOI: 10.1021/jp0208079] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Udo Buck
- Max-Planck-Institut für Strömungsforschung, Bunsenstrasse 10, D-37073 Göttingen, Germany
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49
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50
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