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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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2
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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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Hróðmarsson HR, Kvaran Á. Revealing photofragmentation dynamics through interactions between Rydberg states: REMPI of HI as a case study. Phys Chem Chem Phys 2015; 17:32517-27. [PMID: 26593395 DOI: 10.1039/c5cp06185g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High energy regions of molecular electronic states are largely characterized by the nature and involvement of Rydberg states. Whereas there are a number of observed dynamical processes that are due to interactions between Rydberg and valence states, reports on the corresponding effect of Rydberg-Rydberg state interaction in the literature are scarce. Here we report a detailed characterization of the effects of interactions between two Rydberg states on photofragmentation processes, for a hydrogen halide molecule. Perturbation effects, showing as rotational line shifts, intensity alterations and line-broadenings in REMPI spectra of HI, for two-photon resonance excitations to the j(3)Σ(-)(0(+); v' = 0) and k(3)Π1(v' = 2) Rydberg states, are analyzed. The data reveal pathways of further photofragmentation processes involving photodissociation, autoionization and photoionization affected by the Rydberg-Rydberg state interactions as well as the involvement of other states, close in energy. Detailed mechanisms of the involved processes are proposed.
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Affiliation(s)
| | - Ágúst Kvaran
- Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland.
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4
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Gardiner SH, Lipciuc ML, Karsili TNV, Ashfold MNR, Vallance C. Dynamics of the A-band ultraviolet photodissociation of methyl iodide and ethyl iodide via velocity-map imaging with ‘universal’ detection. Phys Chem Chem Phys 2015; 17:4096-106. [DOI: 10.1039/c4cp04654d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Universal ionization combined with velocity-map imaging allows a comprehensive investigation into the photodissociation dynamics of methyl iodide and ethyl iodide at a range of UV wavelengths within their A-bands.
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Affiliation(s)
- Sara H. Gardiner
- Department of Chemistry
- University of Oxford
- Chemistry Research Laboratory
- Oxford
- UK
| | - M. Laura Lipciuc
- Department of Chemistry
- University of Oxford
- Chemistry Research Laboratory
- Oxford
- UK
| | | | | | - Claire Vallance
- Department of Chemistry
- University of Oxford
- Chemistry Research Laboratory
- Oxford
- UK
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5
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Melchior A, Mark Lambert H, Dagdigian PJ, Bar I, Rosenwaks S. The Photodissociation of Ground and Vibrationally Excited Halogenated Alkanes. Isr J Chem 2013. [DOI: 10.1002/ijch.199700051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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6
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Lin KC. Dynamics and Kinetics of Metal Atoms in the Gas Phase. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.199200085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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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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Xu Y, Qiu X, Abulimiti B, Wang Y, Tang Y, Zhang B. Energy transfer of ethyl iodine studied by time-resolved photoelectron imaging. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.10.041] [Citation(s) in RCA: 3] [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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9
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Rubio-Lago L, García-Vela A, Arregui A, Amaral GA, Bañares L. The photodissociation of CH3I in the red edge of the A-band: Comparison between slice imaging experiments and multisurface wave packet calculations. J Chem Phys 2009; 131:174309. [DOI: 10.1063/1.3257692] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Shubert VA, Rednic M, Pratt ST. Photodissociation of i-C3H7I within the A band and anisotropy-based decomposition of the translational energy distributions. J Chem Phys 2009; 130:134306. [PMID: 19355731 DOI: 10.1063/1.3094321] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The photodissociation of i-propyl iodide in the A absorption band was studied by using velocity map ion imaging following excitation between 304 and 253 nm. The translational energy distributions and translational energy dependence of the angular distributions of the I (2)P(3/2) and (2)P(1/2) photofragments were recorded as a function of the photodissociation wavelength. These distributions are used to decompose the i-C(3)H(7)+I (2)P(3/2) channel into contributions from two processes: Excitation to the (3)Q(0(+)) state followed by crossing onto the (1)Q(1) surface, and direct excitation to the (3)Q(1) surface followed by dissociation on that surface. As in the case of methyl iodide, the former process dominates; the latter process contributes only in the red wing of the absorption band, with its contribution peaking at approximately 287 nm with an absorption of approximately 1% of the band maximum. The data for the i-C(3)H(7)+I(*) (2)P(1/2) channel display a smooth behavior across the full energy range of the present study, and are consistent with direct excitation to the (3)Q(0(+)) surface followed by dissociation on that surface.
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11
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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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12
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Zhang XP, Lee WB, Lin KC. Nonadiabatic Transition in the A-Band Photodissociation of Ethyl Iodide from 294 to 308 nm by Using Velocity Imaging Detection. J Phys Chem A 2008; 113:35-9. [DOI: 10.1021/jp805118w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiao-Peng Zhang
- Department of Chemistry, National Taiwan University, Taipei 106, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - Wei-Bin Lee
- Department of Chemistry, National Taiwan University, Taipei 106, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei 106, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
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13
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Hancock G, Horrocks SJ, Ritchie GAD, Helden JHV, Walker RJ. Time-Resolved Detection of the CF3 Photofragment Using Chirped QCL Radiation. J Phys Chem A 2008; 112:9751-7. [DOI: 10.1021/jp804849m] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- G. Hancock
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - S. J. Horrocks
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - G. A. D. Ritchie
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - J. H. van Helden
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - R. J. Walker
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
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14
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Lee KS, Yeon KY, Jung KH, Kim SK. Direct observation of the primary and secondary C-Br bond cleavages from the 1,2-dibromopropane photodissociation at 234 and 265 nm using the velocity map ion imaging technique. J Phys Chem A 2008; 112:9312-7. [PMID: 18665578 DOI: 10.1021/jp8022666] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photodissociation dynamics of 1,2-dibromopropane has been investigated at 234 and 265 nm by using the velocity map ion imaging method. At both pump energies, a single Gaussian-shaped speed distribution is observed for the Br*((2)P(1/2)) fragment, whereas at least three velocity components are found to be existent for the Br((2)P(3/2)) product. The secondary C-Br bond cleavage of the bromopropyl radical which is energized from the ultrafast primary C-Br bond rupture should be responsible for the multicomponent translational energy distribution at the low kinetic energy region of Br((2)P(3/2)). The recoil anisotropy parameter (beta) of the fragment from the primary C-Br bond dissociation is measured to be 0.53 (0.49) and 1.26 (1.73) for Br((2)P(3/2)) and Br*((2)P(1/2)), respectively, at 234 (265) nm. The beta value of Br((2)P(3/2)) from the secondary C-Br bond dissociation event at 265 nm is found to be 0.87, reflecting the fact that the corresponding Br((2)P(3/2)) fragment carried the initial vector component of the bromopropyl radical produced from the primary bond dissociation event. Density functional theory has been used to calculate energetics involved both in the primary and in the secondary C-Br bond dissociation dynamics.
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Affiliation(s)
- Kyoung-Seok Lee
- Department of Chemistry and School of Molecular Science (BK21), KAIST, Daejeon 305-701, Republic of Korea
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15
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Zhang D, Abdel-hafiez A, Zhang B. Studies on the photodissociation dynamics of HI molecule within the A band range. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.09.026] [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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16
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Lucena JR, Ventura E, do Monte SA, Araújo RCMU, Ramos MN, Fausto R. Dissociation of ground and nσ* states of CF3Cl using multireference configuration interaction with singles and doubles and with multireference average quadratic coupled cluster extensivity corrections. J Chem Phys 2007; 127:164320. [DOI: 10.1063/1.2800020] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Fan H, Pratt ST. Photoionization of hot radicals: C2H5, n-C3H7, and i-C3H7. J Chem Phys 2007; 123:204301. [PMID: 16351250 DOI: 10.1063/1.2110225] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The combination of ion-imaging and vacuum-ultraviolet (vuv) single-photon ionization is used to study the internal energy dependence of the relative photoionization yields of the C(2)H(5),n-C(3)H(7), and i-C(3)H(7) radicals following the 266 nm photodissociation of the corresponding alkyl iodides. The comparison of the ion images obtained by vuv photoionization of the radical with those obtained by two-photon-resonant, three-photon ionization of the complementary I (2)P(32) and I*(2)P(12) atoms allows the extraction of the internal energy dependence of the cross sections. Factors influencing the appearance of the ion images in the different detection channels are discussed, including the secondary fragmentation of the neutral radicals, Franck-Condon factors for the photoionization process, and the unimolecular fragmentation of the parent photoions.
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Affiliation(s)
- Haiyan Fan
- Argonne National Laboratory, Argonne, IL 60439, USA
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18
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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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19
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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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20
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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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21
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Estupiñán EG, Klippenstein SJ, Taatjes CA. Measurements and Modeling of HO2 Formation in the Reactions of n-C3H7 and i-C3H7 Radicals with O2. J Phys Chem B 2005; 109:8374-87. [PMID: 16851983 DOI: 10.1021/jp046514s] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The formation of HO(2) in the reactions of C(2)H(5), n-C(3)H(7), and i-C(3)H(7) radicals with O(2) is investigated using the technique of laser photolysis/long-path frequency-modulation spectroscopy. The alkyl radicals are formed by 266 nm photolysis of alkyl iodides. The formation of HO(2) from the subsequent reaction of the alkyl radicals with O(2) is followed by infrared frequency-modulation spectroscopy. The concentration of I atoms is simultaneously monitored by direct absorption of a second laser probe on the spin-orbit transition. The measured profiles are compared to a kinetic model taken from time-resolved master-equation results based on previously published ab initio characterizations of the relevant stationary points on the potential-energy surface. The ab initio energies are adjusted to produce agreement with the present experimental data and with available literature studies. The isomer specificity of the present results enables refinement of the model for i-C(3)H(7) + O(2) and improved agreement with experimental measurements of HO(2) production in propane oxidation.
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Affiliation(s)
- Edgar G Estupiñán
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, USA
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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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23
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Zheng X, Li YL, Phillips DL. Resonance Raman Study of the Short-Time Photodissociation Dynamics of the A-Band Absorption of Cyclopropyl Iodide in Cyclohexane Solution. J Phys Chem A 2004. [DOI: 10.1021/jp0492772] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xuming Zheng
- Department of Applied Chemistry, Zhejiang Institute of Science and Technology, 88 Wenyi Road, Hangzhou 310033, P. R. China, and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
| | - Yun-Liang Li
- Department of Applied Chemistry, Zhejiang Institute of Science and Technology, 88 Wenyi Road, Hangzhou 310033, P. R. China, and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
| | - David Lee Phillips
- Department of Applied Chemistry, Zhejiang Institute of Science and Technology, 88 Wenyi Road, Hangzhou 310033, P. R. China, and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
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Gu YY, Chojnacki AM, Zietkiewicz CJ, Senin AA, Eden JG. Autoionization in I and I2 observed by multiphoton ionization and photoelectron spectroscopy: Two atomic iodine Rydberg series built on the …5s25p4 3P1 ion core and revised value for the I+(3P1) limit. J Chem Phys 2003. [DOI: 10.1063/1.1625634] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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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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Kavita K, Das PK. Photodissociation of C6H5I, C6F5I, and related iodides in the ultraviolet. J Chem Phys 2002. [DOI: 10.1063/1.1489416] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Senapati D, Kavita K, Das PK. Photodissociation Dynamics of CH2ICl at 222, 236, 266, 280, and ∼304 nm. J Phys Chem A 2002. [DOI: 10.1021/jp026021s] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dulal Senapati
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - K. Kavita
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Puspendu K. Das
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
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Kavita K, Das PK. Photodissociation of Partially Fluorinated Alkyl Iodides in Their A-Band. J Phys Chem A 2001. [DOI: 10.1021/jp0017036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K. Kavita
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Puspendu K. Das
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India
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Zheng X, Kwok WM, Phillips DL. Solvation Effects on the A-Band Photodissociation of Dibromomethane: Turning a Photodissociation into a Photoisomerization†. J Phys Chem A 2000. [DOI: 10.1021/jp001168+] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Alekseyev AB, Liebermann HP, Kokh DB, Buenker RJ. On the ultraviolet photofragmentation of hydrogen iodide. J Chem Phys 2000. [DOI: 10.1063/1.1308552] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Brown A, Balint-Kurti GG. Spin–orbit branching in the photodissociation of HF and DF. II. A time-dependent wave packet study of vibrationally mediated photodissociation. J Chem Phys 2000. [DOI: 10.1063/1.481991] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Brown A, Balint-Kurti GG. Spin–orbit branching in the photodissociation of HF and DF. I. A time-dependent wave packet study for excitation from v=0. J Chem Phys 2000. [DOI: 10.1063/1.482075] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kavita K, Das PK. Dynamics of I*(2P1/2) production from fluorinated alkyl iodides at 266, 280, and ∼305 nm. J Chem Phys 2000. [DOI: 10.1063/1.481445] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Zheng X, Lee CW, Phillips DL. Resonance Raman study of the A-band short-time photodissociation dynamics of axial and equatorial conformers of iodocyclopentane. J Chem Phys 1999. [DOI: 10.1063/1.480488] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Regan PM, Ascenzi D, Clementi C, Ashfold MN, Orr-Ewing AJ. The UV photodissociation of HI revisited: REMPI measurements of I(2P) atom spin–orbit branching fractions. Chem Phys Lett 1999. [DOI: 10.1016/s0009-2614(99)01223-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ford JV, Zhong Q, Poth L, Castleman AW. Femtosecond laser interactions with methyl iodide clusters. I. Coulomb explosion at 795 nm. J Chem Phys 1999. [DOI: 10.1063/1.478530] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Miethke F, Wagner HE, Rutscher A, Gundermann S. Simultaneous Thermal and Plasma Chemical Activation of Conversions in H 2−I 2−HI Mixtures. J Phys Chem A 1999. [DOI: 10.1021/jp982196j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Frank Miethke
- Institute of Physics, Greifswald University, Domstrasse 10a, 17489 Greifswald, FRG
| | - Hans-Erich Wagner
- Institute of Physics, Greifswald University, Domstrasse 10a, 17489 Greifswald, FRG
| | - Alfred Rutscher
- Institute of Physics, Greifswald University, Domstrasse 10a, 17489 Greifswald, FRG
| | - Siegfried Gundermann
- Institute of Physics, Greifswald University, Domstrasse 10a, 17489 Greifswald, FRG
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Zheng X, Phillips DL. Investigation of the short-time photodissociation dynamics of trans-1-bromo-2-iodoethane in the A-band absorption. J Chem Phys 1999. [DOI: 10.1063/1.477805] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Xuming Zheng
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong
| | - David Lee Phillips
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong
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Gendron DJ, Hepburn JW. Dynamics of HI photodissociation in the A band absorption via H-atom Doppler spectroscopy. J Chem Phys 1998. [DOI: 10.1063/1.477356] [Citation(s) in RCA: 35] [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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Eppink ATJB, Parker DH. Methyl iodide A-band decomposition study by photofragment velocity imaging. J Chem Phys 1998. [DOI: 10.1063/1.477087] [Citation(s) in RCA: 178] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Zheng X, Cheng YF, Phillips DL. A-band resonance Raman spectra of 1,2-diiodoethane in cyclohexane solution. Chem Phys Lett 1998. [DOI: 10.1016/s0009-2614(98)00667-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Langford SR, Regan PM, Orr-Ewing AJ, Ashfold MN. On the UV photodissociation dynamics of hydrogen iodide. Chem Phys 1998. [DOI: 10.1016/s0301-0104(98)00013-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Zheng X, Phillips DL. Effect of geometrical conformation on the short-time photodissociation dynamics of 1-iodopropane in the A-band absorption. J Chem Phys 1998. [DOI: 10.1063/1.475988] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Xuming Zheng
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong
| | - David Lee Phillips
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong
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47
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Zheng X, Phillips DL. A-band resonance Raman spectra and short-time photodissociation dynamics of trans 1-chloro-2-iodoethane in cyclohexane solution. Chem Phys Lett 1998. [DOI: 10.1016/s0009-2614(97)01434-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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48
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Kim YS, Kang WK, Kim DC, Jung KH. Photodissociation of tert-Butyl Iodide at 277 and 304 nm: Evidence for Direct and Indirect Dissociation in A-Band Photolysis of Alkyl Iodide. J Phys Chem A 1997. [DOI: 10.1021/jp970574z] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Yong Shin Kim
- Center for Molecular Science and Department of Chemistry, Korea Advanced Institute of Science and Technology, Taeduck Science Town, Taejon 305-701, Korea
| | - Wee Kyung Kang
- Center for Molecular Science and Department of Chemistry, Korea Advanced Institute of Science and Technology, Taeduck Science Town, Taejon 305-701, Korea
| | - Dong-Chan Kim
- Center for Molecular Science and Department of Chemistry, Korea Advanced Institute of Science and Technology, Taeduck Science Town, Taejon 305-701, Korea
| | - Kyung-Hoon Jung
- Center for Molecular Science and Department of Chemistry, Korea Advanced Institute of Science and Technology, Taeduck Science Town, Taejon 305-701, Korea
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49
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KWOK WAIMING, NG POKING, HE GUOZHONG, PHILLIPS DAVIDLEE. Femtosecond photodissociation dynamics of 1,1,1-trifluoro-2The iodoethane in the Franck-Condon region. Mol Phys 1997. [DOI: 10.1080/002689797172949] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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50
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Man S, Kwok WM, Phillips DL, Johnson AE. Short‐time photodissociation dynamics of A‐band and B‐band bromoiodomethane in solution: An examination of bond selective electronic excitation. J Chem Phys 1996. [DOI: 10.1063/1.472426] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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