1
|
Menéndez M, Veselinova A, Zanchet A, Jambrina PG, Aoiz FJ. Rate coefficients for the O + H 2 and O + D 2 reactions: how well ring polymer molecular dynamics accounts for tunelling. Phys Chem Chem Phys 2024; 26:20947-20961. [PMID: 39046374 DOI: 10.1039/d4cp01711k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
We present here extensive calculations of the O(3P) + H2 and O(3P) + D2 reaction dynamics spanning the temperature range from 200 K to 2500 K. The calculations have been carried out using fully converged time-independent quantum mechanics (TI QM), quasiclassical trajectories (QCT) and ring polymer molecular dynamics (RPMD) on the two lowest lying adiabatic potential energy surfaces (PESs), 13A' and 13A'', calculated by Zanchet et al. [J. Chem. Phys., 2019, 151, 094307]. TI QM rate coefficients were determined using the cumulative reaction probability formalism on each PES including all of the total angular momenta and the Coriolis coupling and can be considered to be essentially exact within the Born-Oppenheimer approximation. The agreement between the rate coefficients calculated by using QM and RPMD is excellent for the reaction with D2 in almost the whole temperature range. For the reaction with H2, although the agreement is very good above 500 K, the deviations are significant at lower temperatures. In contrast, the QCT calculations largely underestimate the rate coefficients for the two isotopic variants due to their inability to account for tunelling. The differences found in the disagreements between RPMD and QM rate coefficients for the reactions for both the isotopologues are indicative of the ability of the RPMD method to accurately describe systems where tunelling plays a relevant role. Considering that both reactions are dominated by tunelling below 500 K, the present results show that RPMD is a very powerful tool for determining rate coefficients. The present QM rate coefficients calculated on adiabatic PESs slightly underestimate the best global fits of the experimental measurements, which we attribute to the intersystem crossing with the singlet 11A' PES.
Collapse
Affiliation(s)
- Marta Menéndez
- Departamento de Química Física, Unidad Asociada CSIC, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Anzhela Veselinova
- Departamento de Química Física, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Alexandre Zanchet
- Instituto de Física Fundamental, CSIC, C/Serrano 121-123, 28006 Madrid, Spain
| | - Pablo G Jambrina
- Departamento de Química Física, Universidad de Salamanca, 37008 Salamanca, Spain
| | - F Javier Aoiz
- Departamento de Química Física, Unidad Asociada CSIC, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| |
Collapse
|
2
|
Menéndez M, Jambrina PG, Zanchet A, Verdasco E, Suleimanov YV, Aoiz FJ. New Stress Test for Ring Polymer Molecular Dynamics: Rate Coefficients of the O( 3P) + HCl Reaction and Comparison with Quantum Mechanical and Quasiclassical Trajectory Results. J Phys Chem A 2019; 123:7920-7931. [PMID: 31461272 DOI: 10.1021/acs.jpca.9b06695] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the past decade, ring polymer molecular dynamics (RPMD) has emerged as a very efficient method to determine thermal rate coefficients for a great variety of chemical reactions. This work presents the application of this methodology to study the O(3P) + HCl reaction, which constitutes a stringent test for any dynamical calculation due to rich resonant structure and other dynamical features. The rate coefficients, calculated on the 3A' and 3A″ potential energy surfaces (PESs) by Ramachandran and Peterson [ J. Chem. Phys. 2003 , 119 , 9590 ], using RPMD and quasiclassical trajectories (QCT) are compared with the existing experimental and the quantum mechanical (QM) results by Xie et al. [ J. Chem. Phys. 2005 122 , 014301 ]. The agreement is very good at T > 600 K, although RPMD underestimates rate coefficients by a factor between 4 and 2 in the 200-500 K interval. The origin of these discrepancies lies in the large contribution from tunneling on the 3A″ PES, which is enhanced by resonances due to quasibound states in the van der Waals wells. Although tunneling is fairly well accounted for by RPMD even below the crossover temperature, the effect of resonances, a long-time effect, is not included in the methodology. At the highest temperatures studied in this work, 2000-3300 K, the RPMD rate coefficients are somewhat larger than the QM ones, but this is shown to be due to limitations in the QM calculations and the RPMD are believed to be more reliable.
Collapse
Affiliation(s)
- M Menéndez
- Departamento de Química Física I, Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain
| | - P G Jambrina
- Departamento de Química Física, Facultad de Ciencias Químicas , Universidad de Salamanca , 37008 Salamanca , Spain
| | - A Zanchet
- Departamento de Química Física I, Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain
| | - E Verdasco
- Departamento de Química Física I, Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain
| | - Y V Suleimanov
- Computation-based Science and Technology Research Center , Cyprus Institute , 20 Kavafi Strasse , Nicosia 2121 , Cyprus.,Department of Chemical Engineering , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - F J Aoiz
- Departamento de Química Física I, Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain
| |
Collapse
|
3
|
Zanchet A, Menéndez M, Jambrina PG, Aoiz FJ. New global potential energy surfaces of the ground 3A′ and 3A″ states of the O(3P) + H2 system. J Chem Phys 2019; 151:094307. [DOI: 10.1063/1.5111844] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alexandre Zanchet
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Marta Menéndez
- Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 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 I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| |
Collapse
|
4
|
Product rotational angular momentum polarization of H+FCl (v=0-5; j=0, 3, 6, 9) → HF+Cl and HCl+F at Erel=0.5-20 kcal mol(-1). J Mol Model 2015; 21:309. [PMID: 26564146 DOI: 10.1007/s00894-015-2827-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 09/22/2015] [Indexed: 10/22/2022]
Abstract
The rotational angular momentum polarizations of product molecules of the title reactions on the ground potential energy surface 1 (2)A' of DHTSN [Deskevic et al. J Chem Phys 2006, 124, 224303] have been studied using the quasi-classical trajectory method. Reaction dynamic results of the HF product channel comparing with another channel of HCl with 100,000 trajectories can be accurately resolved. We show the value of the polar p(ϑr) in the range of 0° ≤ ϑr ≤ 180(°), azimuthal p(φr) in the range of 0° ≤ φr ≤ 360(°), and dihedral p(ϑr, φr) in the ranges of 0(°) ≤ ϑr ≤ 180(°) and 0(°) ≤ φr ≤ 360(°); the angular distributions of the product molecules HF and HCl at relative Erel = 0.5, 1, 2, 5, 10, 15, and 20 kcal mol(-1); and four polarization-dependent differential cross sections (PDDCSs) of HF and HCl at Erel = 0.5, 1, 2, 5, 10, and 15 kcal mol(-1). p(φr) distributions at v = 0-5, and j = 0, 3, 6, 9 at every Erel are plotted cylindrically together. The stereo dynamic transformation reaction dependent upon the rovibrational states of the reactant molecule FCl and its relative translational energies around 0.5-5 kcal mol(-1) can be significantly differentiated. Translational and rovibrational enhancements of the title reactions on both early barrier potential energy surfaces have been shown in great detail and clarified. Reaction mechanisms of forward and backward scattering of the product molecules HF and HCl, respectively, have been obtained. Graphical Abstract H + FCl → either HF + Cl (left) or HCl + F (right) is moving along a trajectory on the respective PES.
Collapse
|
5
|
Aoiz FJ, Aldegunde J, Herrero VJ, Sáez-Rábanos V. Comparative dynamics of the two channels of the reaction of D + MuH. Phys Chem Chem Phys 2014; 16:9808-18. [DOI: 10.1039/c3cp53908c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
6
|
Aldegunde J, Jambrina P, García E, Herrero V, Sáez-Rábanos V, Aoiz F. Understanding the reaction between muonium atoms and hydrogen molecules: zero point energy, tunnelling, and vibrational adiabaticity. Mol Phys 2013. [DOI: 10.1080/00268976.2013.815399] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
7
|
Jambrina PG, Lara M, Menéndez M, Launay JM, Aoiz FJ. Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction. J Chem Phys 2013; 137:164314. [PMID: 23126717 DOI: 10.1063/1.4761894] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cumulative reaction probabilities (CRPs) at various total angular momenta have been calculated for the barrierless reaction S((1)D) + H(2) → SH + H at total energies up to 1.2 eV using three different theoretical approaches: time-independent quantum mechanics (QM), quasiclassical trajectories (QCT), and statistical quasiclassical trajectories (SQCT). The calculations have been carried out on the widely used potential energy surface (PES) by Ho et al. [J. Chem. Phys. 116, 4124 (2002)] as well as on the recent PES developed by Song et al. [J. Phys. Chem. A 113, 9213 (2009)]. The results show that the differences between these two PES are relatively minor and mostly related to the different topologies of the well. In addition, the agreement between the three theoretical methodologies is good, even for the highest total angular momenta and energies. In particular, the good accordance between the CRPs obtained with dynamical methods (QM and QCT) and the statistical model (SQCT) indicates that the reaction can be considered statistical in the whole range of energies in contrast with the findings for other prototypical barrierless reactions. In addition, total CRPs and rate coefficients in the range of 20-1000 K have been calculated using the QCT and SQCT methods and have been found somewhat smaller than the experimental total removal rates of S((1)D).
Collapse
Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | | | | | | | | |
Collapse
|
8
|
Suleimanov YV, de Tudela RP, Jambrina PG, Castillo JF, Sáez-Rábanos V, Manolopoulos DE, Aoiz FJ. A ring polymer molecular dynamics study of the isotopologues of the H + H2 reaction. Phys Chem Chem Phys 2013; 15:3655-65. [DOI: 10.1039/c2cp44364c] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
9
|
Jambrina PG, García E, Herrero VJ, Sáez-Rábanos V, Aoiz FJ. Dynamics of the reactions of muonium and deuterium atoms with vibrationally excited hydrogen molecules: tunneling and vibrational adiabaticity. Phys Chem Chem Phys 2012; 14:14596-604. [PMID: 23019575 DOI: 10.1039/c2cp42130e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantum mechanical (QM) and quasiclassical trajectory (QCT) calculations have been carried out for the exchange reactions of D and Mu (Mu = muonium) with hydrogen molecules in their ground and first vibrational states. In all the cases considered, the QM rate coefficients, k(T), are in very good agreement with the available experimental results. In particular, QM calculations on the most accurate potential energy surfaces (PESs) predict a rate coefficient for the Mu + H(2) (ν = 1) reaction which is very close to the preliminary estimate of its experimental value at 300 K. In contrast to the D + H(2) (ν = 0,1) and the Mu + H(2) (ν = 0) reactions, the QCT calculations for Mu + H(2) (ν = 1) predict a much smaller k(T) than that obtained with the accurate QM method. This behaviour is indicative of tunneling. The QM reaction probabilities and total reactive cross sections show that the total energy thresholds for the reactions of Mu with H(2) in ν = 0 and ν = 1 are very similar, whereas for the corresponding reaction with D the ν = 0 total energy threshold is about 0.3 eV lower than that for ν = 1. The results just mentioned can be explained by considering the vibrational adiabatic potentials along the minimum energy path. The threshold for the reaction of Mu with H(2) in both ν = 0 and ν = 1 states is the same and is given by the height of the ground vibrational adiabatic collinear potential, whereas for the D + H(2) reaction the adiabaticity is preserved and the threshold for the reaction in ν = 1 is very close to the height of the ν = 1 adiabatic collinear barrier. For Mu + H(2) (ν = 1) the reaction takes place by crossing from the ν = 1 to the ν = 0 adiabat, since the exit channel leading to MuH (ν = 1) is not energetically accessible. At the lowest possible energies, the non-adiabatic vibrational crossing implies a strong tunneling effect through the ν = 1 adiabatic barrier. Absence of tunneling in the classical calculations results in a threshold that coincides with the height of the ν = 1 adiabatic barrier. Most interestingly, the expected tunneling effect in the reaction of Mu with hydrogen molecules occurs for H(2) (ν = 1) but not for H(2) (ν = 0) where zero-point-energy effects clearly dominate.
Collapse
Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Facultad de Química, Universidad Complutense (Unidad Asociada CSIC), 28040 Madrid, Spain
| | | | | | | | | |
Collapse
|
10
|
YIN SHUHUI, GUO MINGXING, ZOU JINGHAN, XU XUESONG, CHE LI, LI LEI, GAO HONG. PRODUCT ROTATIONAL ANGULAR MOMENTUM POLARIZATION IN REACTIONS D + FCl(v = 0,j = 0) → DCl + F, DF + Cl. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2012. [DOI: 10.1142/s0219633612500538] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A comparative quasi-classical trajectory study on the product alignment and orientation of reactions D + FCl (v,j) → DCl + F , DF + Cl are carried out on a recently computed 12A′ ground-state surface reported by Deskevich et al. The reaction probabilities, integral and differential cross-sections as a function of collision energy are presented. The differential cross-sections and 〈P2(j′ ⋅ k)〉 are governed by different reaction mechanisms for these two reactions. P(θr) and P(ϕr) distributions of products DCl and DF at four selected collision energies of 5, 10, 16 and 30 kcal/mol indicate that DCl and DF product molecules are not only aligned, but also oriented along y-axis. By comparing the P(θr) and P(ϕr) distributions of reactions H + FCl (v = 0,j = 0) → HCl + F and H + FCl (v = 0,j = 0) → HF + Cl , mass factor has some influence on stereodynamics of the title reactions, but the features of PES should have major influence on the difference between dynamics of reactions D + FCl (v = 0,j = 0) → DCl + F and D + FCl (v = 0,j = 0) → DF + Cl .
Collapse
Affiliation(s)
- SHUHUI YIN
- Department of Physics, Dalian Maritime University, Dalian 116026, P. R. China
| | - MINGXING GUO
- Environmental Science and Engineering College, Dalian Maritime University, Dalian 116026, Liaoning, P. R. China
| | - JINGHAN ZOU
- Department of Physics, Dalian Maritime University, Dalian 116026, P. R. China
| | - XUESONG XU
- Department of Physics, Dalian Maritime University, Dalian 116026, P. R. China
| | - LI CHE
- Department of Physics, Dalian Maritime University, Dalian 116026, P. R. China
| | - LEI LI
- Department of Physics, Dalian Maritime University, Dalian 116026, P. R. China
| | - HONG GAO
- Department of Physics, Dalian Maritime University, Dalian 116026, P. R. China
| |
Collapse
|
11
|
Homayoon Z, Jambrina PG, Aoiz FJ, Bowman JM. Communication: Rate coefficients from quasiclassical trajectory calculations from the reverse reaction: The Mu + H2 reaction re-visited. J Chem Phys 2012; 137:021102. [DOI: 10.1063/1.4734316] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
12
|
|
13
|
A quasiclassical trajectory analysis of stereodynamics of the H + FCl (v = 0 – 3, j = 0 – 3) → HCl + F reaction. J CHEM SCI 2011. [DOI: 10.1007/s12039-011-0063-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
|
14
|
Jambrina PG, García E, Herrero VJ, Sáez-Rábanos V, Aoiz FJ. Can quasiclassical trajectory calculations reproduce the extreme kinetic isotope effect observed in the muonic isotopologues of the H + H2 reaction? J Chem Phys 2011; 135:034310. [DOI: 10.1063/1.3611400] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
15
|
Wu VWK. Product rotational angular momentum polarization in the H+FCl(v=0-5, j=0, 3, 6, 9)→HF+Cl reaction. Phys Chem Chem Phys 2011; 13:9407-17. [PMID: 21479325 DOI: 10.1039/c0cp02416c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The product alignment and orientation of the title reaction on the ground potential energy surface of 1 (2)A' have been studied using the quasi-classical trajectory method. The calculations were carried out for case (a) at collision energies of 0.5-20 kcal mol(-1) with the initially rovibrational state of the reagent FCl molecule being at the v = 0 and j = 0 level to especially reveal in detail the dependence of the product integral cross section on collision energy. Further calculations at the collision energy of 15 kcal mol(-1) for case (b) at v = 0-5, and j = 0, and (c) at v = 0, and j = 3, 6, 9 initial states were carried out to reveal the effect of initially vibrational and rotational excitations on stereodynamics, respectively. Possessing final relative velocity k' (defined as a vector in the xz-plane), product alignment perpendicular to the reagent relative velocity vector k (defined as z- or parallel to the z-axis), for case (a) is found to be weaker at all collision energies, for case (b) is found to be vibrationally enhanced by the reactant molecule FCl, but for case (c), rather insensitive to initially rotational excitation. The rotational vector of product molecular orientation pointing to either negative or positive direction of the y-axis in the center of mass frame, e.g. origin of the coordinate system, is enhanced by collision energies regarding to 0.5-20 kcal mol(-1), while it becomes weaker at higher vibrational (v = 0-5) or rotational (j = 0, 3, 6, 9) excitation levels. Effects of collision energies and of rotational excitation at these collision energies, with 15 kcal mol(-1) as an example on the calculated PDDCSs are also shown and discussed. Detailed plots P(φ(r)) in the range of 0 ≤φ(r)≤ 360(o), and P(θ(r), φ(r)) in the ranges of 0 ≤θ(r)≤ 180° and 0 ≤φ(r)≤ 360° at collision energies 0.5-20 kcal mol(-1) have been presented. Overall, results of PDDCSs of the product alignment and product orientation at these collision energies in the title reaction are not very strongly distinguishable.
Collapse
Affiliation(s)
- Victor Wei-Keh Wu
- Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, 80782 Kaohsiung, Taiwan.
| |
Collapse
|
16
|
Peng Y. Quasiclassical Trajectory Calculations of the Isotope Effect: Chemical Stereodynamics for the H(D) + FCl ( v= 0–3, j= 0–3) → HCl(DCl) + F Reactions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2010. [DOI: 10.1246/bcsj.20100022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
17
|
Han B, Zong F, Wang C, Ma W, Zhou J. Product polarization on the 3A″ electronic state in the H+FO reaction and its isotope variant. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.06.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
18
|
Chu T. Quantum mechanics and quasiclassical study of the H/D+FO --> OH/OD+F, HF/DF+O reactions: chemical stereodynamics. J Comput Chem 2009; 31:1385-96. [PMID: 19859917 DOI: 10.1002/jcc.21423] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The time-dependent quantum wave packet and the quasi-classical trajectory (QCT) calculations for the title reactions are carried out using three recent-developed accurate potential energy surfaces of the 1(1)A', 1(3)A', and 1(3)A'' states. The two commonly used polarization-dependent differential cross sections, dsigma(00)/domega(t), dsigma(20)/domega(t), with omega(t) being the polar coordinates of the product velocity omega', and the three angular distributions, P(theta(r)), P(Phi(r)), and P(theta(r),Phi(r)), with theta(r), Phi(r) being the polar angles of the product angular momentum, are generated in the center-of-mass frame using the QCT method to gain insight into the alignment and the orientation of the product molecules. Influences of the potential energy surface, the collision energy, and the isotope mass on the stereodynamics are shown and discussed. Validity of the QCT calculation has been examined and proved in the comparison with the quantum wave packet calculation.
Collapse
Affiliation(s)
- Tianshu Chu
- Institute for Computational Sciences and Engineering, Qingdao University, Qingdao, 266071, China.
| |
Collapse
|
19
|
Jambrina PG, Aoiz FJ, Eyles CJ, Herrero VJ, Sáez Rábanos V. Cumulative reaction probabilities and transition state properties: a study of the H+ + H2 and H+ + D2 proton exchange reactions. J Chem Phys 2009; 130:184303. [PMID: 19449917 DOI: 10.1063/1.3129343] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cumulative reaction probabilities (CRPs) have been calculated by accurate (converged, close coupling) quantum mechanical (QM), quasiclassical trajectory (QCT), and statistical QCT (SQCT) methods for the H(+) + H(2) and H(+) + D(2) reactions at collision energies up to 1.2 eV and total angular momentum J = 0-4. A marked resonance structure is found in the QM CRP, most especially for the H(3)(+) system and J = 0. When the CRPs are resolved in their ortho and para contributions, a clear steplike structure is found associated with the opening of internal states of reactants and products. The comparison of the QCT results with those of the other methods evinces the occurrence of two transition states, one at the entrance and one at the exit. At low J values, except for the quantal resonance structure and the lack of quantization in the product channel, the agreement between QM and QCT is very good. The SQCT model, that reflects the steplike structure associated with the opening of initial and final states accurately, clearly tends to overestimate the value of the CRP as the collision energy increases. This effect seems more marked for the H(+) + D(2) isotopic variant. For sufficiently high J values, the growth of the centrifugal barrier leads to an increase in the threshold of the CRP. At these high J values the discrepancy between SQCT and QCT becomes larger and is magnified with growing collision energy. The total CRPs calculated with the QCT and SQCT methods allowed the determination of the rate constant for the H(+) + D(2) reaction. It was found that the rate, in agreement with experiment, decreases with temperature as expected for an endothermic reaction. In the range of temperatures between 200 and 500 K the differences between SQCT and QCT rate results are relatively minor. Although exact QM calculations are formidable for an exact determination of the k(T), it can be reliably expected that their value will lie between those given by the dynamical and statistical trajectory methods.
Collapse
Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Universidad de Salamanca, 37008 Salamanca, Spain
| | | | | | | | | |
Collapse
|
20
|
Aoiz FJ, Herrero VJ, Rábanos VS. Cumulative reaction probabilities and transition state properties: A study of the F+H2 reaction and its deuterated isotopic variants. J Chem Phys 2008; 129:024305. [DOI: 10.1063/1.2952672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
21
|
Aoiz FJ, González-Lezana T, Sáez Rábanos V. A comparison of quantum and quasiclassical statistical models for reactions of electronically excited atoms with molecular hydrogen. J Chem Phys 2008; 129:094305. [DOI: 10.1063/1.2969812] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
22
|
Aoiz FJ, González-Lezana T, Sáez Rábanos V. Stringent test of the statistical quasiclassical trajectory model for the H3+ exchange reaction: A comparison with rigorous statistical quantum mechanical results. J Chem Phys 2007; 127:174109. [DOI: 10.1063/1.2774982] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|