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Zanchet A, Roncero O, Karabulut E, Solem N, Romanzin C, Thissen R, Alcaraz C. The role of intersystem crossing in the reactive collision of S+(4S) with H2. J Chem Phys 2024; 161:044302. [PMID: 39037135 DOI: 10.1063/5.0214447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Accepted: 07/05/2024] [Indexed: 07/23/2024] Open
Abstract
We report a study on the reactive collision of S+(4S) with H2, HD, and D2 combining guided ion beam experiments and quantum-mechanical calculations. It is found that the reactive cross sections reflect the existence of two different mechanisms, one being spin-forbidden. Using different models, we demonstrate that the spin-forbidden pathway follows a complex mechanism involving three electronic states instead of two as previously thought. The good agreement between theory and experiment validates the methodology employed and allows us to fully understand the reaction mechanism. This study also provides new fundamental insights into the intersystem crossing process.
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Affiliation(s)
- Alexandre Zanchet
- Instituto de Física Fundamental, CSIC, Serrano 123, 28006 Madrid, Spain
| | - Octavio Roncero
- Instituto de Física Fundamental, CSIC, Serrano 123, 28006 Madrid, Spain
| | - Ezman Karabulut
- Vocational School of Health Services, Bitlis Eren University, 13000 Bitlis, Turkey
| | - Nicolas Solem
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France and Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette, France
| | - Claire Romanzin
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France and Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette, France
| | - Roland Thissen
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France and Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette, France
| | - Christian Alcaraz
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France and Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette, France
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2
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Mazo-Sevillano PD, Aguado A, Goicoechea JR, Roncero O. Quantum study of the CH3+ photodissociation in full-dimensional neural network potential energy surfaces. J Chem Phys 2024; 160:184307. [PMID: 38738612 DOI: 10.1063/5.0206895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 04/22/2024] [Indexed: 05/14/2024] Open
Abstract
C H 3 + , a cornerstone intermediate in interstellar chemistry, has recently been detected for the first time by using the James Webb Space Telescope. The photodissociation of this ion is studied here. Accurate explicitly correlated multi-reference configuration interaction ab initio calculations are done, and full-dimensional potential energy surfaces are developed for the three lower electronic states, with a fundamental invariant neural network method. The photodissociation cross section is calculated using a full-dimensional quantum wave packet method in heliocentric Radau coordinates. The wave packet is represented in angular and radial grids, allowing us to reduce the number of points physically accessible, requiring to push up the spurious states appearing when evaluating the angular kinetic terms, through projection technique. The photodissociation spectra, when employed in astrochemical models to simulate the conditions of the Orion bar, result in a lesser destruction of CH3+ compared to that obtained when utilizing the recommended values in the kinetic database for astrochemistry.
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Affiliation(s)
- Pablo Del Mazo-Sevillano
- Unidad Asociada UAM-IFF-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Alfredo Aguado
- Unidad Asociada UAM-IFF-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Javier R Goicoechea
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
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Menéndez M, Garcia E, Lara M, Jambrina PG, Aoiz FJ. Li + HF and Li + HCl Reactions Revisited I: QCT Calculations and Simulation of Experimental Results. J Phys Chem A 2023; 127:6924-6944. [PMID: 37579497 PMCID: PMC10461305 DOI: 10.1021/acs.jpca.3c03763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 07/20/2023] [Indexed: 08/16/2023]
Abstract
The Li + HF and Li + HCl reactions share some common features. They have the same kinematics, relatively small barrier heights, bent transition states, and are both exothermic when the zero point energy is considered. Nevertheless, the pioneering crossed beam experiments by Lee and co-workers in the 80s (Becker et al., J. Chem. Phys. 1980, 73, 2833) revealed that the dynamics of the two reactions differ significantly, especially at low collision energies. In this work, we present theoretical simulations of their results in the laboratory frame (LAB), based on quasiclassical trajectories and obtained using accurate potential energy surfaces. The calculated LAB angular distributions and time-of-flight spectra agree well with the raw experimental data, although our simulations do not reproduce the experimentally derived center-of-mass (CM) differential cross section and velocity distributions. The latter were derived by forward convolution fitting under the questionable assumption that the CM recoil velocity and scattering angle distribution were uncoupled, while our results show that the coupling between them is relevant. Some important insights into the reaction mechanism discussed in the article by Becker et al. had not been contrasted with those that can be extracted from the theoretical results. Among them, the correlation between the angular momenta involved in the reactions has also been examined. Given the kinematics of both systems, the reagent orbital angular momentum, l , is almost completely transformed into the rotation of the product diatom, j'. However, contrary to the coplanar mechanism proposed in the original paper, we find that the initial and final relative orbital angular momenta are not necessarily parallel. Both reactions are found to be essentially direct, although about 15% of the LiFH complexes live longer than 200 fs.
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Affiliation(s)
- Marta Menéndez
- Departamento
de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Ernesto Garcia
- Departamento
de Química Física, Universidad
del País Vasco (UPV/EHU), 01006 Vitoria, Spain
| | - Manuel Lara
- Departamento
de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28039 Madrid, Spain
| | - Pablo G. Jambrina
- Departamento
de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, 37008 Salamanca, Spain
| | - F. Javier Aoiz
- Departamento
de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
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4
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Karabulut E. Oxygen Molecule Formation and the Puzzle of Nitrogen Dioxide and Nitrogen Oxide during Lightning Flash. J Phys Chem A 2022; 126:5363-5374. [PMID: 35920809 DOI: 10.1021/acs.jpca.2c02378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Unlike the compounds of the natural air atmosphere, the lightning systems are primarily focused on NO(X2Π), NO2(12A'), and O(3P) concentrations that occurred newly and highly in the ground electronic structure. While the NO/NO2 concentrations ratio is about 2000 during the lightning flash, this ratio becomes about 0.8 right after the lightning flash. The reason for this decrease in the ratio is the disappearance of the high temperature that prevents the formation of NO2 (with the combination of NO and O) and of the photon energy that causes its dissociation (NO2 + hv → NO + O) right after the lightning flash. However, this study will focus on the reactions that contribute to the NO concentration, except for the combination of N and O atoms during lightning flash. To do this, it was focused on the reactive scattering states (especially the NO-exchange) of the NO + O collision and the photo-dissociation of NO2, which provide the formation of the NO molecule in the ground electronic state. This case raises important questions. To what extent do the NO-exchange reaction and the photo-dissociation of NO2 contribute to the atmospherically observed NO molecules? or how can the vibrational quantum states of the NO molecules formed by the photo-dissociation be effected on the NO + O1 collision to produce a NO1 molecule? These conditions may contribute to the concentrations of NO high during lightning flashes. Under low collision energy (between 0.1 and 0.3 eV), the NO (v = 0) population dissociated by a photon can act as reactants in the NO-exchange reactive scattering on the doublet electronic state. Since it is assumed that all of the NO2 molecules are due to NO in the lightning flash system, this is one of the reasons that makes the NO population so high during lightning flash. Therefore, in the light of considering that the lightning system supports the formation of highly vibrating molecular groups, it might also support the formation of O2 molecules. In particular, it was shown that the v = 4 quantum state of the NO molecule over the doublet state between collision energies of 0.9-1.5 eV and the v = 5 quantum state of the NO molecule over the quartet state between collision energies of 1.0-1.5 eV contribute to O2 formation.
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Affiliation(s)
- Ezman Karabulut
- Vocational School of Health Service, Bitlis Eren University, 13000 Bitlis, Turkey
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5
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Sanz-Sanz C, Aguado A, Roncero O. Near-resonant effects in the quantum dynamics of the H + H 2 + → H 2 + H + charge transfer reaction and isotopic variants. J Chem Phys 2021; 154:104104. [PMID: 33722048 DOI: 10.1063/5.0044320] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The non-adiabatic quantum dynamics of the H + H2 + → H2 + H+ charge transfer reactions, and some isotopic variants, is studied with an accurate wave packet method. A recently developed 3 × 3 diabatic potential model is used, which is based on very accurate ab initio calculations and includes the long-range interactions for ground and excited states. It is found that for initial H2 +(v = 0), the quasi-degenerate H2(v' = 4) non-reactive charge transfer product is enhanced, producing an increase in the reaction probability and cross section. It becomes the dominant channel from collision energies above 0.2 eV, producing a ratio between v' = 4 and the rest of v's, which that increase up to 1 eV. The H + H2 + → H2 + + H exchange reaction channel is nearly negligible, while the reactive and non-reactive charge transfer reaction channels are of the same order, except that corresponding to H2(v' = 4), and the two charge transfer processes compete below 0.2 eV. This enhancement is expected to play an important vibrational and isotopic effect that needs to be evaluated. For the three proton case, the problem of the permutation symmetry is discussed when using reactant Jacobi coordinates.
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Affiliation(s)
- Cristina Sanz-Sanz
- Unidad Asociada UAM-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Alfredo Aguado
- Unidad Asociada UAM-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
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6
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Liu X, Xie C, Guo H. A new potential energy surface and state-to-state quantum dynamics of the Li + HF → H + LiF reaction. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.01.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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7
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Tan RS, Zhai HC, Yan W, Gao F, Lin SY. A new ab initio potential energy surface of LiClH (1A') system and quantum dynamics calculation for Li + HCl (v = 0, j = 0-2) → LiCl + H reaction. J Chem Phys 2017; 146:164305. [PMID: 28456188 DOI: 10.1063/1.4982066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A new ab initio potential energy surface (PES) for the ground state of Li + HCl reactive system has been constructed by three-dimensional cubic spline interpolation of 36 654 ab initio points computed at the MRCI+Q/aug-cc-pV5Z level of theory. The title reaction is found to be exothermic by 5.63 kcal/mol (9 kcal/mol with zero point energy corrections), which is very close to the experimental data. The barrier height, which is 2.99 kcal/mol (0.93 kcal/mol for the vibrationally adiabatic barrier height), and the depth of van der Waals minimum located near the entrance channel are also in excellent agreement with the experimental findings. This study also identified two more van der Waals minima. The integral cross sections, rate constants, and their dependence on initial rotational states are calculated using an exact quantum wave packet method on the new PES. They are also in excellent agreement with the experimental measurements.
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Affiliation(s)
- Rui Shan Tan
- School of Physics, Shandong University, Jinan 250100, China
| | - Huan Chen Zhai
- School of Physics, Shandong University, Jinan 250100, China
| | - Wei Yan
- School of Physics, Shandong University, Jinan 250100, China
| | - Feng Gao
- School of Physics, Shandong University, Jinan 250100, China
| | - Shi Ying Lin
- School of Physics, Shandong University, Jinan 250100, China
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Aguado A, Roncero O, Zanchet A, Agúndez M, Cernicharo J. The Photodissociation of HCN and HNC: Effects on the HNC/HCN Abundance Ratio in the Interstellar Medium. THE ASTROPHYSICAL JOURNAL 2017; 838:33. [PMID: 28522878 PMCID: PMC5433558 DOI: 10.3847/1538-4357/aa63ee] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The impact of the photodissociation of HCN and HNC isomers is analyzed in different astrophysical environments. For this purpose, the individual photodissociation cross section of HCN and HNC isomers have been calculated in the 7-13.6 eV photon energy range for a temperature of 10 K. These calculations are based on the ab initio calculation of three-dimensional adiabatic potential energy surfaces of the 21 lower electronic states. The cross sections are then obtained using a quantum wave packet calculation of the rotational transitions needed to simulate a rotational temperature of 10 K. The cross section calculated for HCN shows significant differences with respect to the experimental one, and this is attributed to the need of considering non-adiabatic transitions. Ratios between the photodissociation rates of HCN and HNC under different ultraviolet radiation fields have been computed by renormalizing the rates to the experimental one. It is found that HNC is photodissociated faster than HCN by a factor of 2.2, for the local interstellar radiation field, and 9.2, for the solar radiation field at 1 au. We conclude that to properly describe the HNC/HCN abundance ratio in astronomical environments illuminated by an intense ultraviolet radiation field it is necessary to use different photodissociation rates for each of the two isomers, obtained by integrating the product of the photodissociation cross sections and ultraviolet radiation field over the relevant wavelength range.
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Affiliation(s)
- Alfredo Aguado
- Departamento de Química Física Aplicada (UAM), Unidad Asociada a IFF-CSIC, Facultad de Ciencias Módulo 14, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
| | - Alexandre Zanchet
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
| | - Marcelino Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, Cantoblanco 28049, Spain
| | - José Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, Cantoblanco 28049, Spain
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9
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Vieira D, Krems RV, Tscherbul TV. Molecular collisions and reactive scattering in external fields: Are field-induced couplings important at short range? J Chem Phys 2017; 146:024102. [PMID: 28088162 DOI: 10.1063/1.4973431] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We use accurate quantum scattering calculations to elucidate the role of short-range molecule-field interactions in atom-molecule inelastic collisions and abstraction chemical reactions at low temperatures. We consider two examples: elastic and inelastic scattering of NH(Σ3) molecules with Mg(S1) atoms in a magnetic field; reactive scattering LiF + H → Li + HF in an electric field. Our calculations suggest that, for non-reactive collision systems and abstraction chemical reactions, the molecule-field interactions cannot generally be neglected at short range because the atom-molecule potential passes through zero at short range. An important exception occurs for Zeeman transitions in atom-molecule collisions at magnetic fields ≲1000 G, for which the molecule-field couplings need only be included at large ρ outside the range of the atom-molecule interaction. Our results highlight the importance of an accurate description of ρ-dependent molecule-field interactions in quantum scattering calculations on molecular collisions and chemical reactions at low temperatures.
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Affiliation(s)
- D Vieira
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - R V Krems
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - T V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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Chenel A, Roncero O, Aguado A, Agúndez M, Cernicharo J. Photodissociation of HCN and HNC isomers in the 7-10 eV energy range. J Chem Phys 2016; 144:144306. [PMID: 27083720 PMCID: PMC4894478 DOI: 10.1063/1.4945389] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ultraviolet photoabsorption spectra of the HCN and HNC isomers have been simulated in the 7-10 eV photon energy range. For this purpose, the three-dimensional adiabatic potential energy surfaces of the 7 lowest electronic states, and the corresponding transition dipole moments, have been calculated, at multireference configuration interaction level. The spectra are calculated with a quantum wave packet method on these adiabatic potential energy surfaces. The spectra for the 3 lower excited states, the dissociative electronic states, correspond essentially to predissociation peaks, most of them through tunneling on the same adiabatic state. The 3 higher electronic states are bound, hereafter electronic bound states, and their spectra consist of delta lines, in the adiabatic approximation. The radiative lifetime towards the ground electronic states of these bound states has been calculated, being longer than 10 ns in all cases, much longer that the characteristic predissociation lifetimes. The spectra of HCN is compared with the available experimental and previous theoretical simulations, while in the case of HNC there are no previous studies to our knowledge. The spectrum for HNC is considerably more intense than that of HCN in the 7-10 eV photon energy range, which points to a higher photodissociation rate for HNC, compared to HCN, in astrophysical environments illuminated by ultraviolet radiation.
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Affiliation(s)
- Aurelie Chenel
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
| | - Alfredo Aguado
- Departamento de Química Física Aplicada (UAM), Unidad Asociada a IFF-CSIC, Facultad de Ciencias Módulo 14, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Marcelino Agúndez
- Instituto de Ciencias de Materiales (CCMM-CSIC), C.S.I.C., Cantoblanco, 28049 Madrid, Spain
| | - José Cernicharo
- Instituto de Ciencias de Materiales (CCMM-CSIC), C.S.I.C., Cantoblanco, 28049 Madrid, Spain
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Li WT, Chen MD, Sun ZG. Quantum Dynamics of Li+HF/DF Reaction Investigated by a State-to-State Time-dependent Wave Packet Approach. CHINESE J CHEM PHYS 2015. [DOI: 10.1063/1674-0068/28/cjcp1507151] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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12
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Bulut N, Kłos J, Roncero O. Quantum mechanical calculations of state-to-state cross sections and rate constants for the F + DCl → Cl + DF reaction. J Chem Phys 2015; 142:214310. [PMID: 26049499 DOI: 10.1063/1.4922110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present accurate state-to-state quantum wave packet calculations of integral cross sections and rate constants for the title reaction. Calculations are carried out on the best available ground 1(2)A' global adiabatic potential energy surface of Deskevich et al. [J. Chem. Phys. 124, 224303 (2006)]. Converged state-to-state reaction cross sections have been calculated for collision energies up to 0.5 eV and different initial rotational and vibrational excitations, DCl(v = 0, j = 0 - 1; v = 1, j = 0). Also, initial-state resolved rate constants of the title reaction have been calculated in a temperature range of 100-400 K. It is found that the initial rotational excitation of the DCl molecule does not enhance reactivity, in contract to the reaction with the isotopologue HCl in which initial rotational excitation produces an important enhancement. These differences between the isotopologue reactions are analyzed in detail and attributed to the presence of resonances for HCl(v = 0, j), absent in the case of DCl(v = 0, j). For vibrational excited DCl(v = 1, j), however, the reaction cross section increases noticeably, what is also explained by another resonance.
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Affiliation(s)
- Niyazi Bulut
- Department of Physics, Firat University, 23169 Elazig˜, Turkey
| | - Jacek Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742-2021, USA
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
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13
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He X, Chao (Wu) VWK, Han K, Hao C, Zhang Y. Mechanism of the collision energy and reagent vibration’s effects on the collision time for the reaction Ca+HCl. COMPUT THEOR CHEM 2015. [DOI: 10.1016/j.comptc.2014.12.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Krasilnikov MB, Popov RS, Roncero O, De Fazio D, Cavalli S, Aquilanti V, Vasyutinskii OS. Polarization of molecular angular momentum in the chemical reactions Li + HF and F + HD. J Chem Phys 2013; 138:244302. [DOI: 10.1063/1.4809992] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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CHENG JIE, YUE XIANFANG. QUASICLASSICAL TRAJECTORY STUDY OF STEREODYNAMICS FOR THE REACTIONS Li+ HF/DF/TF. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2013. [DOI: 10.1142/s0219633613500089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Stereodynamics of the reaction Li + HF (v = 0,j = 0) → LiF + H and its isotopic variants on the ground electronic state (12A′) potential energy surface (PES) are studied by employing the quasiclassical trajectory (QCT) method. At a collision energy of 2.2 kcal/mol, product rotational angular momentum distributions, P(θr) and P(ϕr), are calculated in the center-of-mass (CM) frame. The results demonstrate that the product rotational angular momentum j′ is not only aligned along the direction perpendicular to the reagent relative velocity vector k, but also oriented along the negative y-axis. The four generalized polarization-dependent differential cross sections (PDDCSs) are also computed. The PDDCS00 distribution shows a sideways scattering for the reaction Li + HF and a strongly backward scattering for the reaction Li + DF . However, it displays both the forward and backward scatterings for the reaction Li + TF . These features demonstrate that the Li + HF and Li + DF reactions proceed predominantly through the direct reaction mechanism. However, the Li + TF reaction undergoes both the direct and indirect reaction mechanisms. The PDDCS21- distribution indicates that the product angular distributions are anisotropic.
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Affiliation(s)
- JIE CHENG
- Department of Physics and Information Engineering, Jining University, Qufu 273155, P. R. China
| | - XIAN-FANG YUE
- Department of Physics and Information Engineering, Jining University, Qufu 273155, P. R. China
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16
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Yue XF, Wang MS. Isotope effects on product polarization and reaction mechanism in the Li+HF(v=0,j=0)→LiF+H reaction. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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17
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González-Sánchez L, Vasyutinskii O, Zanchet A, Sanz-Sanz C, Roncero O. Quantum stereodynamics of Li + HF reactive collisions: the role of reactants polarization on the differential cross section. Phys Chem Chem Phys 2011; 13:13656-69. [DOI: 10.1039/c0cp02452j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Zanchet A, Roncero O, González-Lezana T, Rodríguez-López A, Aguado A, Sanz-Sanz C, Gómez-Carrasco S. Differential Cross Sections and Product Rotational Polarization in A + BC Reactions Using Wave Packet Methods: H+ + D2 and Li + HF Examples. J Phys Chem A 2009; 113:14488-501. [DOI: 10.1021/jp9038946] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Zanchet
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - O. Roncero
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - T. González-Lezana
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - A. Rodríguez-López
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - A. Aguado
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - C. Sanz-Sanz
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
| | - S. Gómez-Carrasco
- Instituto de Física Fundamental, CSIC, Unidad Asociada UAM-CSIC, Serrano 123, 28006 Madrid, Spain, Centro de Supercomputación de Galicia, Av. de Vigo s/n (Campus Sur), 15706 Santiago de Compostela, Spain, and Departamento de Química Física, Facultad de Ciencias C-XIV, Unidad Asociada UAM-CSIC, Universidad Autónoma de Madrid, 28049, Madrid, Spain, School of Chemistry, University of Birmingham, Edbaston, Birmingham B15 2TT, United Kingdom, and Theoretical Chemistry Department, Institute of Physical
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19
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Gloaguen E, Sanz Sanz C, Collier M, Gaveau MA, Soep B, Roncero O, Mestdagh JM. Transition-state spectroscopy of the photoinduced Ca + CH3F reaction. 3. Reaction following the local excitation to Ca(4s3d 1D). J Phys Chem A 2008; 112:1408-20. [PMID: 18232672 DOI: 10.1021/jp077664g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Ca* + CH3F --> CaF* + CH3 reaction was studied both experimentally and theoretically. The reaction was photoinduced in Ca...CH3F complexes, which were illuminated by a tunable laser in the range 18 000-24 000 cm-1. The absorption band that leads to the reaction extends between 19 000 and 23 000 cm-1. It is formed of three broad overlapping structures corresponding to the excitation of different electronic states of the complex. The two structures of lowest energy were considered in detail. They are associated with two series of respectively 2 and 3 molecular states correlating to Ca(4s3d 1D) + CH3F at infinite separation between Ca and CH3F. The assignment of these structures to specific electronic transitions of the complex stemmed from theoretical calculations where the Ca...CH3F complex is described by a linear Ca-F-C backbone. 2D potential energy surfaces were calculated by associating a pseudopotential description of the [Ca2+] and [F7+] cores, a core polarization operator on calcium, an extensive Gaussian basis, and a treatment of the electronic problem at the CI-MRCI level. All the excited levels correlating to the 4s2 1S, 4s3d 1D, and 4s4p 1P levels of Ca in the Ca + CH3F channel were documented in a calculation that explored the rearrangement channels where either Ca + CH3F or CaF + CH3 are formed. Then, wavepacket calculations on the 2D-PES's allowed one to simulate the absorption spectrum of the complex, in an approximation where the various electronic states of the complex are not coupled together. The assignment above stemmed from this. The second outcome of the calculation was that whatever the excited level of the complex that is considered, the reaction has to proceed through energy barriers. The electronic excitation of the complex on the red side of the absorption band does not seem to deposit enough energy in the system to overcome these barriers (even the lowest one) or to stimulate tunneling reactions. An alternative reaction mechanism involving a transfer to triplet PES's is proposed.
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Affiliation(s)
- E Gloaguen
- Laboratoire Francis Perrin (CNRS-URA-2453), DSM/IRAMIS/Service des Photons, Atomes et Molécules, C.E.A. Saclay, F-91191 Gif-sur-Yvette cedex, France
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20
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Transition state spectroscopy of open shell systems: Angle-resolved photodetachment spectra for the adiabatic singlet states of OHF. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2007.01.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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21
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Weck PF, Balakrishnan N. Importance of long-range interactions in chemical reactions at cold and ultracold temperatures. INT REV PHYS CHEM 2006. [DOI: 10.1080/01442350600791894] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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22
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Sanz C, van der Avoird A, Roncero O. Collisional and photoinitiated reaction dynamics in the ground electronic state of Ca-HCl. J Chem Phys 2005; 123:64301. [PMID: 16122302 DOI: 10.1063/1.1995700] [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
Ca+HCl(upsilon,j) reactive collisions were studied for different rovibrational states of the HCl reactant using wave-packet calculations in reactant Jacobi coordinates. A recently proposed potential-energy surface was used with a barrier of approximately 0.4 eV followed by a deep well. The possibility of an insertion mechanism due to this last well has been analyzed and it was found that once the wave packet passes over the barrier most of it goes directly to CaCl+H products, which shows that the reaction dynamics is essentially direct. It was also found that there is no significant change in the reaction efficiency as a function of the initial HCl rovibrational state, because CaHCl at the barrier has an only little elongated HCl bond. Near the threshold for reaction with HCl(upsilon=0), however, the reaction shows significant steric effects for j > 0. In a complementary study, the infrared excitation from the Ca-HCl van der Waals well was simulated. The spectrum thus obtained shows several series of resonances which correspond to quasibound states correlating to excited HCl(upsilon) vibrations. The Ca-HCl binding energies of these quasibound states increase dramatically with upsilon, from 75 to 650 cm(-1), because the wave function spreads increasingly over larger HCl bond lengths. Thus it explores the region of the barrier saddle point and the deep insertion well. Although also the charge-transfer contribution increases with upsilon, the reaction probability for resonances of the upsilon=2 manifold, which are well above the reaction threshold, is still negligible. This explains the relatively long lifetimes of these upsilon=2 resonances. The reaction probability becomes significant at upsilon=3. Our simulations have shown that an experimental study of this type will allow a gradual spectroscopic probing of the barrier for the reaction.
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Affiliation(s)
- Cristina Sanz
- Instituto de Matemáticas y Física Fundamental, Consejo Superior de Investigaciones Científicas (CSIC), Serrano 123, 28006 Madrid, Spain
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23
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Weck PF, Balakrishnan N. Heavy atom tunneling in chemical reactions: Study of H+LiF collisions. J Chem Phys 2005; 122:234310. [PMID: 16008444 DOI: 10.1063/1.1930847] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The H+LiF(X (1)sigma(+),upsilon=0-2,j=0)-->HF(X (1)sigma(+),upsilon',j')+Li(2S) bimolecular process is investigated by means of quantum scattering calculations on the chemically accurate X 2A' LiHF potential energy surface of Aguado et al. [A. Aguado, M. Paniagua, C. Sanz, and J. Roncero, J. Chem. Phys. 119, 10088 (2003)]. Calculations have been performed for zero total angular momentum for translational energies from 10(-7) to 10(-1) eV. Initial-state selected reaction probabilities and cross sections are characterized by resonances originating from the decay of metastable states of the H...F-Li and Li...F-H van der Waals complexes. Extensive assignment of the resonances has been carried out by performing quasibound states calculations in the entrance and exit channel wells. Chemical reactivity is found to be significantly enhanced by vibrational excitation at low temperatures, although reactivity appears much less favorable than nonreactive processes due to the inefficient tunneling of the relatively heavy fluorine atom strongly bound in van der Waals complexes.
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Affiliation(s)
- P F Weck
- Department of Chemistry, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada 89154, USA.
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24
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Verbockhaven G, Sanz C, Groenenboom GC, Roncero O, van der Avoird A. Ab initiopotential-energy surface for the reaction Ca+HCl→CaCl+H. J Chem Phys 2005; 122:204307. [PMID: 15945724 DOI: 10.1063/1.1899154] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The potential-energy surface of the ground electronic state of CaHCl has been obtained from 6400 ab initio points calculated at the multireference configuration-interaction level and represented by a global analytical fit. The Ca+HCl-->CaCl+H reaction is endothermic by 5100 cm(-1) with a barrier of 4470 cm(-1) at bent geometry, taking the zero energy in the Ca+HCl asymptote. On both sides of this barrier are potential wells at linear geometries, a shallow one due to van der Waals interactions in the entrance channel, and a deep one attributed to the H(-)Ca(++)Cl(-) ionic configuration. The accuracy of the van der Waals well depth, approximately 200 cm(-1), was checked by means of additional calculations at the coupled-cluster singles and doubles with perturbative triples level and it was concluded that previous empirical estimates are unrealistic. Also, the electric dipole function was calculated, analytically fitted in the regions of the two wells, and used to analyze the charge shifts along the reaction path. In the insertion well, 16,800 cm(-1) deep, the electric dipole function confirmed the ionic structure of the HCaCl complex and served to estimate effective atomic charges. Finally, bound rovibrational levels were computed both in the van der Waals well and in the insertion well, and the infrared-absorption spectrum of the insertion complex was simulated in order to facilitate its detection.
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Affiliation(s)
- Gilles Verbockhaven
- Institute of Theoretical Chemistry, Institute for Molecules and Materials, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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25
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Weck PF, Balakrishnan N. Quantum dynamics of the Li+HF→H+LiF reaction at ultralow temperatures. J Chem Phys 2005; 122:154309. [PMID: 15945637 DOI: 10.1063/1.1884115] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quantum-mechanical calculations are reported for the Li+HF(v=0,1,j=0)-->H+LiF(v',j') bimolecular scattering process at low and ultralow temperatures. Calculations have been performed for zero total angular momentum using a recent high-accuracy potential-energy surface for the X2A' electronic ground state. For Li+HF(v=0,j=0), the reaction is dominated by resonances due to the decay of metastable states of the Li cdots,...F-H van der Waals complex. Assignment of these resonances has been carried out by calculating the eigenenergies of the quasibound states. We also find that while chemical reactivity is greatly enhanced by vibrational excitation, the resonances get mostly washed out in the reaction of vibrationally excited HF with Li atoms. In addition, we find that at low energies, the reaction is significantly suppressed due to the less-efficient tunneling of the relatively heavy fluorine atom.
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Affiliation(s)
- P F Weck
- Department of Chemistry, University of Nevada Las Vegas, Las Vegas, Nevada 89154, USA.
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26
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González-Sánchez L, Gómez-Carrasco S, Aguado A, Paniagua M, Hernández ML, Alvariño JM, Roncero O. Transition state dynamics of OHF on several electronic states: photodetachment spectrum of OHF- and conical intersections. J Chem Phys 2004; 121:9865-75. [PMID: 15549859 DOI: 10.1063/1.1807375] [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
Wave packet simulations of the photodetachment spectrum of OHF(-) are performed on several electronic adiabatic states, two triplets and four singlets of neutral OHF. The transition moments to these six states have been approximated using the ab initio electronic wave functions of OHF(-) and OHF calculated at the equilibrium configuration of the parent anion. In a first step, two-dimensional simulations of the spectrum are performed on new two-dimensional potential energy surfaces (PESs) of the neutral in a OHF collinear geometry. The resulting simulated spectrum is in rather good agreement with the experimental one, reproducing all the structures from 0 to 2.5 eV electron kinetic energies. At energies below 0.5 eV, all calculated states, singlets and triplets, contribute to the total spectrum. At higher energies, however, only the triplet states participate. In a second step, to improve the description of the spectrum, three-dimensional wave packet simulations of the spectrum are performed, getting an excellent agreement with the experiment. The collinear (3)Sigma(-) and (3)Pi states split in two (3)A(") and one (3)A('). New adiabatic PESs are used in this work for the 2 (3)A(") and 1 (3)A(') states, while the one recently proposed was used for the ground 1 (3)A("). It is found that the minimum energy paths of the (3)Sigma(-) and (3)Pi states cross twice at collinear geometry, so that at the transition state the ground state corresponds to (3)Pi, while (3)Sigma(-) is the lowest state otherwise. Such conical intersections are expected to give rise to important Sigma-Pi vibronic effects, requiring a complete three-dimensional model of coupled diabatic states to improve our understanding of the reaction dynamics in this kind of systems.
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Affiliation(s)
- Lola González-Sánchez
- Unidad Asociada UAM-CSIC, Instituto de Matemáticas y Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
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27
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Goldstein R, Figl C, Grosser J, Hoffmann O, Jungen M, Stalder J, Rebentrost F. Collision photography: polarization imaging of atom-molecule collisions. J Chem Phys 2004; 121:8769-74. [PMID: 15527340 DOI: 10.1063/1.1799592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report differential scattering experiments on the laser excitation of Na + M collision pairs with M = N(2), CO, C(2)H(2), and CO(2). The collision event is probed by the laser polarization revealing geometric and electronic properties of the collision pair. The experimental data are compared to the results of a Monte Carlo trajectory simulation using ab initio quantum chemical data.
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Affiliation(s)
- R Goldstein
- Institut für Atom- und Molekülphysik, Universität Hannover, 30167 Hannover, Germany
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28
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González-Sánchez L, Gómez-Carrasco S, Aguado A, Paniagua M, Hernández ML, Alvariño JM, Roncero O. Photodetachment spectrum of OHF[sup −]: Three-dimensional study of the heavy–light–heavy resonances. J Chem Phys 2004; 121:309-20. [PMID: 15260549 DOI: 10.1063/1.1756581] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this work a simulation of the OHF(-) photodetachment spectrum is performed in a three-dimensional potential energy surface recently developed for OHF((3)A(")). The ground (2)A(') state potential of the anion is calculated in three dimensions based on accurate ab initio calculations and the reaction dynamics is studied using a wave packet method. The calculated spectrum shows a sequence of bands associated to vibrational HF(v) up to v=3. Each band is formed by a continuous spectrum and resonant structures. These resonances are associated to the OH-F channel well of the (3)A(") PES, in which fragmentation occurs through vibrational predissociation. Above the OH(v=0) threshold a new resonant pattern appears corresponding to heavy-light-heavy resonances. Special attention is paid to the assignment of these resonances because they mediate the reaction dynamics in the OH+F collision at low kinetic energies. The sequence of bands is in rather good agreement with that appearing in the experimental spectrum, especially at higher electron kinetic energies. At low kinetic energies, however, some other electronic states may contribute. The resonance structures might be washed out by the rotational average and the relatively low energy resolution of the experiment.
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Affiliation(s)
- Lola González-Sánchez
- Unidad Asociada UAM-CSIC, Instituto de Matemáticas y Física Fundamental, C.S.I.C., Serrano 123, 28006 Madrid, Spain
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