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Abstract
Nonstatistical dynamics is important for many chemical reactions. The Rice-Ramsperger-Kassel-Marcus (RRKM) theory of unimolecular kinetics assumes a reactant molecule maintains a statistical microcanonical ensemble of vibrational states during its dissociation so that its unimolecular dynamics are time independent. Such dynamics results when the reactant's atomic motion is chaotic or irregular. Intrinsic non-RRKM dynamics occurs when part of the reactant's phase space consists of quasiperiodic/regular motion and a bottleneck exists, so that the unimolecular rate constant is time dependent. Nonrandom excitation of a molecule may result in short-time apparent non-RRKM dynamics. For rotational activation, the 2J + 1 K levels for a particular J may be highly mixed, making K an active degree of freedom, or K may be a good quantum number and an adiabatic degree of freedom. Nonstatistical dynamics is often important for bimolecular reactions and their intermediates and for product-energy partitioning of bimolecular and unimolecular reactions. Post–transition state dynamics is often highly complex and nonstatistical.
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Affiliation(s)
- Bhumika Jayee
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA
| | - William L. Hase
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, USA
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Teplukhin A, Ivanov M, Babikov D. Frozen rotor approximation in the mixed quantum/classical theory for collisional energy transfer: Application to ozone stabilization. J Chem Phys 2013; 139:124301. [DOI: 10.1063/1.4821349] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Semenov A, Babikov D. Equivalence of the Ehrenfest theorem and the fluid-rotor model for mixed quantum/classical theory of collisional energy transfer. J Chem Phys 2013; 138:164110. [DOI: 10.1063/1.4801430] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Ivanov MV, Babikov D. Mixed quantum-classical theory for the collisional energy transfer and the rovibrational energy flow: application to ozone stabilization. J Chem Phys 2011; 134:144107. [PMID: 21495742 DOI: 10.1063/1.3576103] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A mixed quantum-classical approach to the description of collisional energy transfer is proposed in which the vibrational motion of an energized molecule is treated quantum mechanically using wave packets, while the collisional motion of the molecule and quencher and the rotational motion of the molecule are treated using classical trajectories. This accounts rigorously for quantization of vibrational states, zero-point energy, scattering resonances, and permutation symmetry of identical atoms, while advantage is taken of the classical scattering regime. Energy is exchanged between vibrational, rotational, and translational degrees of freedom while the total energy is conserved. Application of this method to stabilization of the van der Waals states in ozone is presented. Examples of mixed quantum-classical trajectories are discussed, including an interesting example of supercollision. When combined with an efficient grid mapping procedure and the reduced dimensionality approximation, the method becomes very affordable computationally.
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Affiliation(s)
- Mikhail V Ivanov
- Chemistry Department, Wehr Chemistry Building, Marquette University, Milwaukee, Wisconsin 53201-1881, USA
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Lourderaj U, Hase WL. Theoretical and Computational Studies of Non-RRKM Unimolecular Dynamics. J Phys Chem A 2009; 113:2236-53. [DOI: 10.1021/jp806659f] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Upakarasamy Lourderaj
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061
| | - William L. Hase
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061
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Wei J, Tröllsch A, Tesch C, Temps F. Rotational state-dependent mixings between resonance states of vibrationally highly excited DCO (X̃ 2A′). J Chem Phys 2004; 120:10530-42. [PMID: 15268080 DOI: 10.1063/1.1724825] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Rotational state-dependent mixings between highly excited resonance states of DCO (X (2)A(')) were investigated by stimulated emission pumping spectroscopy via a series of intermediate rotational levels in the B (2)A(') electronic state of the radical. Two examples for such interactions, between pairs of accidentally nearly degenerate vibrational states at energies of E(v) approximately 6450 and E(v) approximately 10 060 cm(-1), respectively, were analyzed in detail. Deperturbations of the measured spectra provided the zeroth-order vibration-rotation term energies, widths, and rotational constants of the states and the absolute values of the vibrational coupling matrix elements. The coupled states turned out to have very different A rotational constants so that their mixings switch on or off as they are tuned relative to each other as function of the K(a) rotational quantum number. The respective zeroth-order states could be assigned to different interlaced vibrational polyads. Thus, when two states belonging to different polyads are accidentally nearly isoenergetic, even very weak interpolyad interactions may start to play important roles. The derived interpolyad coupling elements are small compared to the typical intrapolyad coupling terms so that their influences on the vibrational term energies are small. However, large effects on the widths (i.e., decay rates) of the states can be observed even from weak coupling terms when a narrow, long-lived state is perturbed by a broad, highly dissociative state. This influence contributes to the previously observed strong state-to-state fluctuations of the unimolecular decay rates of the DCO radical as function of vibrational excitation. Similar mechanisms are likely to promote the transition to "statistical" rates in many larger molecules.
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Affiliation(s)
- J Wei
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
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Azzam T, Schinke R, Farantos SC, Joyeux M, Peterson KA. The bound state spectrum of HOBr up to the dissociation limit: Evolution of saddle-node bifurcations. J Chem Phys 2003. [DOI: 10.1063/1.1569914] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Grebenshchikov S, Schinke R, Hase W. State-specific dynamics of unimolecular dissociation. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0069-8040(03)80005-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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Song K, Sun L, Hase WL, Grebenshchikov SY, Schinke R. Relationship between Mode Specific and Thermal Unimolecular Rate Constants for HOCl → OH + Cl Dissociation. J Phys Chem A 2002. [DOI: 10.1021/jp014689l] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Weiß J, Hauschildt J, Schinke R, Haan O, Skokov S, Bowman JM, Mandelshtam VA, Peterson KA. The unimolecular dissociation of the OH stretching states of HOCl: Comparison with experimental data. J Chem Phys 2001. [DOI: 10.1063/1.1412602] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Brandt-Pollmann U, Weiß J, Schinke R. The unimolecular dissociation of HCO. V. Mixings between resonance states. J Chem Phys 2001. [DOI: 10.1063/1.1412601] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Weiß J, Schinke R. Renner–Teller induced predissociation of HNO(Ã 1A″): Rotational-state dependent linewidths of quasibound states. J Chem Phys 2001. [DOI: 10.1063/1.1384456] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Bowman JM, Irle S, Morokuma K, Wodtke A. Dipole moments of highly vibrationally excited HCN: Theoretical prediction of an experimental diagnostic for delocalized states. J Chem Phys 2001. [DOI: 10.1063/1.1364681] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Zou S, Skokov S, Bowman JM. Ab initio calculation of resonance energies and widths of HOCl(7νOH and 8νOH) and comparison with experiment. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)00297-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Alferova T, Andersson S, Elander N, Levin S, Yarevsky E. Finite element three-body studies of bound and resonant states in atoms and molecules. ADVANCES IN QUANTUM CHEMISTRY 2001. [DOI: 10.1016/s0065-3276(01)40023-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Joyeux M, Sugny D, Lombardi M, Jost R, Schinke R, Skokov S, Bowman J. Vibrational dynamics up to the dissociation threshold: A case study of two-dimensional HOCl. J Chem Phys 2000. [DOI: 10.1063/1.1321031] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Weiß J, Hauschildt J, Grebenshchikov SY, Düren R, Schinke R, Koput J, Stamatiadis S, Farantos SC. Saddle-node bifurcations in the spectrum of HOCl. J Chem Phys 2000. [DOI: 10.1063/1.480563] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hauschildt J, Weiß J, Schinke R. Influence of Vibrational Resonances and Coriolis Coupling on Dissociation Rates in the Near-threshold Unimolecular Fragmentation of HOCl. ACTA ACUST UNITED AC 2000. [DOI: 10.1524/zpch.2000.214.5.609] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The unimolecular dissociation of HOCl in the ground electronic state near the HO+Cl fragmentation threshold is investigated employing an ab initio potential energy surface. The dynamics calculations are performed by using an imaginary absorbing potential and filter diagonalization. The computational study is mainly focused on the influence of accidental or systematic vibrational resonances on the total angular momentum dependence of dissociation rates and the importance of Coriolis interaction.
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Chen R, Guo H, Skokov S, Bowman JM. Theoretical studies of rotation induced Fermi resonances in HOCl. J Chem Phys 1999. [DOI: 10.1063/1.480053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Dutton G, Barnes RJ, Sinha A. State selected unimolecular dissociation of HOCl near threshold: The 6νOH vibrational state. J Chem Phys 1999. [DOI: 10.1063/1.479757] [Citation(s) in RCA: 37] [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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Skokov S, Bowman JM. Complex L2 calculation of the variation of resonance widths of HOCl with total angular momentum. J Chem Phys 1999. [DOI: 10.1063/1.479752] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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