1
|
Matsugi A. Potential Nonstatistical Effects on the Unimolecular Decomposition of H 2O 2. J Phys Chem A 2022; 126:4482-4496. [PMID: 35766950 DOI: 10.1021/acs.jpca.2c03501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An attempt is made to evaluate the nonstatistical effects in the thermal decomposition of hydrogen peroxide (H2O2). Previous experimental studies on this reaction reported an unusual pressure dependence of the rate constant indicating broader falloff behavior than expected from conventional theory. In this work, the possibility that the rate constant is affected by nonstatistical effects is investigated based on classical trajectory calculations on the global potential energy surfaces of H2O2 and H2O2 + Ar. The emphasis is on the intramolecular energy redistribution from the K-rotor, that is, the external rotor for rotation around the principal axis of least moment of inertia. The calculations for the H2O2 molecules excited above the dissociation threshold suggest that the energy redistribution from the torsion and K-rotor to vibrations can be competitive with dissociation. In particular, the slow redistribution of the energy associated with the K-rotor significantly affects the dissociation rate. The successive trajectory calculations for collisions of H2O2 with Ar show that the energy associated with the K-rotor can be collisionally transferred more efficiently than the vibrational energy. On the basis of these results and several assumptions, a simple model is proposed to account for the nonstatistical effects on the pressure-dependent thermal rate constants. The model predicts significant broadening of the falloff curve of the rate constants but still cannot fully explain the experimental data.
Collapse
Affiliation(s)
- Akira Matsugi
- National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| |
Collapse
|
2
|
|
3
|
|
4
|
Monte Carlo stochastic simulation of the master equation for unimolecular reaction systems. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/b978-0-444-64207-3.00007-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
5
|
Leitner DM. Molecules and the Eigenstate Thermalization Hypothesis. ENTROPY 2018; 20:e20090673. [PMID: 33265762 PMCID: PMC7513195 DOI: 10.3390/e20090673] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/02/2018] [Accepted: 09/03/2018] [Indexed: 11/18/2022]
Abstract
We review a theory that predicts the onset of thermalization in a quantum mechanical coupled non-linear oscillator system, which models the vibrational degrees of freedom of a molecule. A system of N non-linear oscillators perturbed by cubic anharmonic interactions exhibits a many-body localization (MBL) transition in the vibrational state space (VSS) of the molecule. This transition can occur at rather high energy in a sizable molecule because the density of states coupled by cubic anharmonic terms scales as N3, in marked contrast to the total density of states, which scales as exp(aN), where a is a constant. The emergence of a MBL transition in the VSS is seen by analysis of a random matrix ensemble that captures the locality of coupling in the VSS, referred to as local random matrix theory (LRMT). Upon introducing higher order anharmonicity, the location of the MBL transition of even a sizable molecule, such as an organic molecule with tens of atoms, still lies at an energy that may exceed the energy to surmount a barrier to reaction, such as a barrier to conformational change. Illustrative calculations are provided, and some recent work on the influence of thermalization on thermal conduction in molecular junctions is also discussed.
Collapse
Affiliation(s)
- David M Leitner
- Department of Chemistry, University of Nevada, Reno, NV 89557, USA
| |
Collapse
|
6
|
Carpenter BK, Harvey JN, Orr-Ewing AJ. The Study of Reactive Intermediates in Condensed Phases. J Am Chem Soc 2016; 138:4695-705. [DOI: 10.1021/jacs.6b01761] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Barry K. Carpenter
- School
of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, U.K
| | - Jeremy N. Harvey
- Department
of Chemistry, KU Leuven, Celestijnen Laan 200F, B-3001 Heverlee, Belgium
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| |
Collapse
|
7
|
Affiliation(s)
- John R. Barker
- Department
of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109-2143, United States
| | - Michael Frenklach
- Department
of Mechanical Engineering, University of California—Berkeley, Berkeley, California 94720-1740, United States
| | - David M. Golden
- Department
of Mechanical Engineering, Stanford University, Stanford, California 94305-3032, United States
| |
Collapse
|
8
|
Ioffe IN, Granovsky AA. Photoisomerization of Stilbene: The Detailed XMCQDPT2 Treatment. J Chem Theory Comput 2013; 9:4973-90. [PMID: 26583415 DOI: 10.1021/ct400647w] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report the detailed XMCQDPT2/cc-pVTZ study of trans-cis photoisomerization in one of the core systems of both experimental and computational photochemistry-the stilbene molecule. For the first time, the potential energy surface (PES) of the S1 state has been directly optimized and scanned using a multistate multiconfiguration second-order perturbation theory. We characterize the trans-stilbene, pyramidalized (phantom), and DHP-cis-stilbene geometric domains of the S1 state and describe their stationary points including the transition states between them, as well as S1/S0 intersections. Also reported are the minima and the activation barriers in the ground state. Our calculations correctly predict the kinetic isotope effect due to H/D exchange at ethylenic hydrogens, the dynamic behavior of excited cis-stilbene, and trans-cis branching ratio after relaxation to S0 through a rather unsymmetric conical intersection. In general, the XMCQDPT2 results confirm the qualitative adequacy of the TDDFT (especially SF-TDDFT) picture of the excited stilbene but also reveal quantitative discrepancies that deserve further exploration.
Collapse
Affiliation(s)
- I N Ioffe
- Department of Chemistry, Lomonosov Moscow State University , Moscow, 119991, Russia
| | | |
Collapse
|
9
|
Kovalenko SA, Dobryakov AL, Pollak E, Ernsting NP. Communication: Optical cooling of trans-stilbene. J Chem Phys 2013; 139:011101. [DOI: 10.1063/1.4812776] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
10
|
Sajadi M, Ernsting NP. Excess Dynamic Stokes Shift of Molecular Probes in Solution. J Phys Chem B 2013; 117:7675-84. [DOI: 10.1021/jp400473n] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Mohsen Sajadi
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, D-12489 Berlin, Germany
| | - Nikolaus P. Ernsting
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, D-12489 Berlin, Germany
| |
Collapse
|
11
|
Kovalenko S, Dobryakov A. On the excitation wavelength dependence and Arrhenius behavior of stilbene isomerization rates in solution. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.03.073] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
12
|
Sebree JA, Zwier TS. The excited states and vibronic spectroscopy of diphenyldiacetylene and diphenylvinylacetylene. Phys Chem Chem Phys 2012; 14:173-83. [DOI: 10.1039/c1cp22857a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
13
|
Tranca DC, Neufeld AA. Quantum-classical modeling of photoisomerization of polyatomic molecules. J Chem Phys 2010; 132:134109. [DOI: 10.1063/1.3368644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
14
|
|
15
|
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
| |
Collapse
|
16
|
Tatchen J, Pollak E. Ab initiospectroscopy and photoinduced cooling of thetrans-stilbene molecule. J Chem Phys 2008; 128:164303. [DOI: 10.1063/1.2895041] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
17
|
Leitner DM, Gruebele M. A quantum model of restricted vibrational energy flow on the way to the transition state in unimolecular reactions. Mol Phys 2008. [DOI: 10.1080/00268970701854789] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
18
|
Maranzana A, Barker JR, Tonachini G. Master equation simulations of competing unimolecular and bimolecular reactions: application to OH production in the reaction of acetyl radical with O2. Phys Chem Chem Phys 2007; 9:4129-41. [PMID: 17687463 DOI: 10.1039/b705116f] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Master equation calculations were carried out to simulate the production of hydroxyl free radicals initiated by the reaction of acetyl free radicals (CH3(C=O).) with molecular oxygen. In particular, the competition between the unimolecular reactions and bimolecular reactions of vibrationally excited intermediates was modeled by using a single master equation. The vibrationally excited intermediates (isomers of acetylperoxyl radicals) result from the initial reaction of acetyl free radical with O2. The bimolecular reactions were modeled using a novel pseudo-first-order microcanonical rate constant approach. Stationary points on the multi-well, multi-channel potential energy surface (PES) were calculated at the DFT(B3LYP)/6-311G(2df,p) level of theory. Some additional calculations were carried out at the CASPT2(7,5)/6-31G(d) level of theory to investigate barrierless reactions and other features of the PES. The master equation simulations are in excellent agreement with the experimental OH yields measured in N2 or He buffer gas near 300 K, but they do not explain a recent report that the OH yields are independent of pressure in nearly pure O2 buffer gas.
Collapse
Affiliation(s)
- Andrea Maranzana
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA
| | | | | |
Collapse
|
19
|
Robertson SH, Pilling MJ, Jitariu LC, Hillier IH. Master equation methods for multiple well systems: application to the 1-,2-pentyl system. Phys Chem Chem Phys 2007; 9:4085-97. [PMID: 17687460 DOI: 10.1039/b704736c] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The master equation (ME) provides a powerful technique for modeling reactions that involve at least one potential energy well. It can be widely applied to reactions with several connected energy wells and multiple product channels. The application of the technique is reviewed by reference to the H + SO(2) reaction, where phenomenological rate constants for use, for example, in a combustion model can be extracted through an analysis of the eigenvalues and eigenvectors of the collision matrix, M, that describes formation of the adducts HSO(2) and HOSO from the source H + SO(2), collisional energy transfer in the adduct wells and reaction via the product channel (sink) OH + SO. The approach is extended to systems with more than one sink and it is demonstrated that macroscopic (phenomenological) rate coefficients derived from a ME obey detailed balance if the original ME is appropriately constructed. The method has been applied to the 1-, 2-pentyl radical system, that includes isomerisation and dissociation via two channels to form C(3)H(6) + C(2)H(5) and C(2)H(4) + C(3)H(7). The calculations clearly demonstrate the importance of indirect dissociation channels, in which an isomer can dissociate to form the product set to which it is not directly connected, e.g. formation of C(3)H(6) + C(2)H(5) from 1-pentyl, via the energized states of 2-pentyl. As in previous studies of pentyl dissociation, there is a convergence of the chemically significant eigenvalues and the internal energy relaxation eigenvalues above approximately 1000 K; the consequences of this convergence are discussed.
Collapse
|