1
|
Pan H, Liu K. State-to-State Dynamics in Mode-Specific Reactions of Cl + CH 3D( v1-I, v1-II, and v4 = 1; |10⟩): Loss of Memory or Not. J Phys Chem Lett 2023; 14:1769-1776. [PMID: 36762846 DOI: 10.1021/acs.jpclett.3c00133] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Several decades of the study of reaction dynamics culminate in the concept of mode specificity and bond selectivity in polyatomic systems. Until very recently, the main concern of those studies has been total reactivity and little attention has been paid to the mode-specific effects on the more detailed product-state and angular distributions. Conventional wisdom would anticipate that the fine detail should reveal a more pronounced mode dependency. However, a few recent studies showed that the product distributions could appear to be surprisingly insensitive to the modes of internal excitation of reagents. This counterintuitive finding led to a concept of loss of memory. Here, we present detailed experimental results in the reactions of the Cl atom with three distinct stretching-excited CH3D(vCH3 = 1) reagents. In conjunction with the previous reports on various aspects of this reaction, such a comprehensive set of data enables us to perform an in-depth examination of the validity of this new concept.
Collapse
Affiliation(s)
- Huilin Pan
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, P. R. China
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China
- Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, Taiwan 80424
| |
Collapse
|
2
|
Mondal S, Pan H, Liu K. Stretching-mode specificity in the Cl + CH 3D( v1-I, v1-II, and v4 = 1; | jK〉) reactions: dependency on the initial | jK〉 selectivity. Phys Chem Chem Phys 2022; 24:24050-24061. [PMID: 36168830 DOI: 10.1039/d2cp03614b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The title reactions were studied at a collisional energy of 5.4 kcal mol-1 in a crossed-beam product-imaging experiment. The dynamics attributes of the dominant ground-state CH2D(00) and the accompanied C-D bend-excited CH2D(61) products were imaged in reactions with totally 16 ro-vibrationally selected states of the CH3D(vi, |jK〉) reagents. We found that all three vibrational excitations yielded marked |jK〉-dependent rate-enhancements in forming the (00, 0/1)s product pairs. Furthermore, for a given rotational |jK〉-mode, a vibrational-mode propensity of v4 > v1-I > v1-II in rate promotion and a clear manifestation of the Fermi-phase-induced interference effect of the latter two were observed. Compared to the reactivity of the rotationless state |jK〉 = |00〉, a minute rotational-excitation of all three stretch-excited CH3D(vi = 1) reagents could yield significantly higher reaction rates for the product pair (00, 0)s, but not so for (00, 1)s. The signals in forming the (61, 0)s pair were clearly notable but smaller than that of the ground-state reaction product pair, (00, 0)g. An opposite propensity of v1-II ≈ v1-I > v4 with a milder dependency on the initial |jK〉-states was observed. The angular distributions of the (00, 0)s pairs were nearly identical for all ro-vibrationally excited reagents, displaying the typical trait for a direct abstraction of the rebound mechanism. Similar distributions were found for the (61, 0)s pairs; yet, both pairs deviated substantially from the peripheral feature of the ground-state reaction pair of (00, 0)g. Those of the (00, 1)s pairs in reactions with v4-excitation featured a prominent forward-peaking distribution-suggestive of a time-delayed, resonance-mediated pathway, again with little dependency on the initial |jK〉-states. As for the reactions with the two Fermi-dyads, v1-I and v1-II, albeit showing globally similar distributions to that for v4, a substantial variation with the initial rotational-mode excitation could be discerned in the forward-peaking features. To unravel the impact of the Fermi-phase on the |jK〉-dependent attributes, we adopted a comparative approach by contrasting the observations in reactions with the Fermi-dyad reagents (the superposition states) to those with the pure-state reagents. Remarkable distinctions are unveiled and elucidated with the unexplained results explicitly pointed out, which call for future theoretical investigations for deeper understanding.
Collapse
Affiliation(s)
- Sohidul Mondal
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei, 10699, Taiwan.
| | - Huilin Pan
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei, 10699, Taiwan. .,Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei, 10699, Taiwan. .,Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian, 116023, P. R. China
| |
Collapse
|
3
|
Mondal S, Liu K. Imaging the Mode-Specificity in Cl + CH 3D( v1-I, v1-II, v4 = 1; | jK⟩ = |10⟩) → CH 2D(4 1) + HCl( v). J Phys Chem A 2022; 126:2825-2831. [PMID: 35499972 DOI: 10.1021/acs.jpca.2c01852] [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
We report a crossed-beam imaging experiment on the title reactions at two collisional energies (Ec) of 5.3 and 10 kcal mol-1. Both the integral cross sections relative to the ground-state reactivity and the differential cross sections were measured and compared. We found that one-quantum excitations of the CH3-stretching vibrations of the CH3D reagent exerted profound mode-specificity in forming the umbrella-mode-excited CH2D(41) products with the vibrational efficacy of v4 > v1-I > v1-II at both Ec values. The concomitantly formed HCl(v) coproducts were vibrationally cold. Interestingly, the branching ratios of (v = 1)/(v = 0) appeared invariant to the initial stretch-modes of excitation at Ec = 5.3 kcal mol-1, yet exhibited a pronounced mode-specific dependency in the order of v1-II > v1-I > v4 at Ec = 10.3 kcal mol-1. This large and Ec-dependent disparity between the two Fermi-coupled reagents, v1-I and v1-II, is particularly significant and could be another facet─in addition to that in the recently reported vibrational enhancement factors─of the Fermi-phase-induced interference effect manifested in the product vibrational branching ratio. The pair-correlated angular distributions (vCH2D, vHCl)s = (41, 0)s in the three stretch-excited reactions were globally alike and resembled that of the ground-state reaction pair (00, 0)g, suggestive of a direct abstraction mechanism of the peripheral type. This is in sharp contrast to all other vibrationally excited pairs of (11, 0)s, (31, 0)s, and (61, 0)s previously reported in the CH2D + HCl isotopic channel, for which both the direct abstraction and a time-delayed resonance pathway partake.
Collapse
Affiliation(s)
- Sohidul Mondal
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, 10617, Taiwan
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, 10617, Taiwan.,Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian, 116023, P. R. China
| |
Collapse
|
4
|
Pan H, Liu K. Pair-Correlated Imaging of Cl + CH 3D( v4, v1-I, v1-II = 1, | jK⟩) → CH 2D( vi) + HCl( v). J Phys Chem A 2021; 125:6731-6738. [PMID: 34333974 DOI: 10.1021/acs.jpca.1c05373] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The title reactions were studied at a collisional energy of 10.0 kcal mol-1 in a crossed-beam, product-imaging experiment. In terms of integral cross sections, all three CH3-stretching excited CH3D(vCH3 = 1) reagents promote the reactivity in forming the predominant product pair of (vCH2D, vHCl)s = (00, 0/1)s with a prominent mode-propensity of v4 > v1-I > v1-II, where v4 denotes the degenerate mode of CH3 asymmetric stretch and v1-I and v1-II are a pair of Fermi-coupled, symmetric-stretch states. The vibrationally excited CH2D product pairs of (61, 0)s, (11, 0)s, and (31, 0)s appear to be minor channels and display a reverse propensity of v4 < v1-I ≈ v1-II for (61, 0)s, while v4 > v1-I for (11, 0)s. Based on the observed angular distributions, we conjecture that, irrespective of the initial mode of excitation, the (00, 0)s product pair proceeds by a direct abstraction of the peripheral type, whereas the (00,1)s pair is mediated via a resonance pathway. Intriguingly, the angular distributions of the excited product pairs-(61, 0)s, (11, 0)s, and (31, 0)s-are remarkably similar and comprise the traits of both the peripheral mechanism and resonance pathway. Possible interpretation and implication are suggested. In addition, due to the spectral overlap of the REMPI bands and heavily congested image features, a robust data analysis method is developed, which enables us to extract the dynamics attributes of a weak feature buried in the proximate, more intense ones with high fidelity.
Collapse
Affiliation(s)
- Huilin Pan
- Southern University of Science and Technology, Shenzhen 518055, P. R. China.,Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China.,Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, Taiwan 80424
| |
Collapse
|
5
|
Pan H, Liu K. Active stereo-control of the Cl + CH 4(ν 3 = 1) reaction: a three-dimensional perspective. Phys Chem Chem Phys 2020; 22:10949-10956. [PMID: 32377655 DOI: 10.1039/d0cp01502d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The transition state in Cl + CH4 is of Cl-H-C collinear geometry. As the reactant CH4 is vibrationally excited by a linearly polarized infrared (IR) light to the antisymmetric-stretching state of ν3 = 1, all four C-H bonds are collectively excited and any one of the H-atoms can be reactive. Yet, a strong alignment of the excited CH4(ν3 = 1), as evidenced from the striking stereo-specificity in the Cl + CH4 reaction, was clearly revealed in a previous, exploratory study. Reported here is the full account of that investigation at two collisional energies of Ec = 4.8 and 2.7 kcal mol-1, using a crossed molecular-beam, product-imaging approach. By active control of the polarization direction of an IR laser under judiciously chosen beam-geometries, a complete set of polarization-dependent differential cross sections is disentangled from the CH3(00) product images. To our surprise, the quantitative results appear nearly identical to those obtained for the isotope-substituted reaction of Cl + CHD3(ν1 = 1) → HCl(ν) + CD3(00). A detailed discussion is presented to elucidate the underlying physics for such an intriguing similarity in stereo-reactivity between a spherical-top and a symmetric-top reactant.
Collapse
Affiliation(s)
- Huilin Pan
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei, 10617, Taiwan. and Southern University of Science and Technology, Shenzhen, P. R. China.
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P. O. Box 23-166, Taipei, 10617, Taiwan. and State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS, Dalian 116023, P. R. China and Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| |
Collapse
|
6
|
Abstract
It has long been predicted that oscillatory behavior exists in reactivity as a function of collision energy for heavy-light-heavy (HLH) chemical reactions in which a light atom is transferred between two heavy atoms or groups of atoms, but direct observation of such a behavior in bimolecular reactions remains a challenge. Here we report a joint theoretical and crossed-molecular-beam study on the Cl + CH4 → HCl + CH3 reaction. A distinctive peak at a collision energy of 0.15 eV for the CH3(v = 0) product was experimentally detected in the backward scattering direction. Detailed quantum-dynamics calculations on a highly accurate potential energy surface revealed that this feature originates from the reactivity oscillation in this HLH polyatomic reaction. We anticipate that such reactivity oscillations exist in many HLH reactions involving polyatomic reagents.
Collapse
|
7
|
Mondal S, Liu K. Effects of Stretching Excitations in Cl + CH3D(v4, v1-I, v1-II = 1): As the Cl Atom Attacks the Unexcited C–D Bond. J Phys Chem A 2019; 123:1514-1520. [DOI: 10.1021/acs.jpca.8b11702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sohidul Mondal
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10699
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10699
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan 80424
| |
Collapse
|
8
|
Bhattacharyya S, Mondal S, Liu K. Imaging a Resonance-Dominant Polyatomic Reaction: F + CH 3D → CH 3(ν 2 = 2) + DF(ν). J Phys Chem Lett 2018; 9:5502-5507. [PMID: 30188130 DOI: 10.1021/acs.jpclett.8b02517] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The title reaction was studied in a crossed-beam scattering experiment at the collisional energy ( Ec) ranging from 0.46 to 4.53 kcal mol-1. Using a time-sliced velocity-imaging technique, both the pair-correlated integral and differential cross sections were measured. On the basis of the observed structures in state-specific excitation functions and the patterns in the Ec evolution of product angular distributions, we inferred that the title reaction proceeds predominantly via a resonance-mediated pathway, in contrast to the previous findings in the isotopically analogous reactions where the alternative direct abstraction pathway often dominates the reactivity. Despite the complexity of numerous scattering resonances involved in this six-atom reaction, extending our understanding of the isolated resonance in the analogous benchmark F + HD (H2) reaction enables us to propose plausible mechanistic origins for the formation as well as the decay of the complicated overlapped resonances.
Collapse
Affiliation(s)
- Surjendu Bhattacharyya
- Institute of Atomic and Molecular Sciences (IAMS) , Academia Sinica , P.O. Box 23-166, Taipei , 10617 , Taiwan
| | - Sohidul Mondal
- Institute of Atomic and Molecular Sciences (IAMS) , Academia Sinica , P.O. Box 23-166, Taipei , 10617 , Taiwan
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS) , Academia Sinica , P.O. Box 23-166, Taipei , 10617 , Taiwan
- Department of Physics , National Taiwan University , Taipei , 10617 , Taiwan
| |
Collapse
|
9
|
Pan H, Tkac O, Liu K. Rotational-mode specific effects on the stereo-requirement in the reaction of prealigned-CHD3(v1 = 1; |JK = |10 or |1 ± 1) with the chlorine atom. J Chem Phys 2018; 148:244307. [DOI: 10.1063/1.5037892] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Huilin Pan
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
| | - Ondrej Tkac
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| |
Collapse
|
10
|
Pan H, Wang F, Czakó G, Liu K. Direct mapping of the angle-dependent barrier to reaction for Cl + CHD3 using polarized scattering data. Nat Chem 2017; 9:1175-1180. [DOI: 10.1038/nchem.2858] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 07/28/2017] [Indexed: 11/09/2022]
|
11
|
Pan H, Liu K, Caracciolo A, Casavecchia P. Crossed beam polyatomic reaction dynamics: recent advances and new insights. Chem Soc Rev 2017; 46:7517-7547. [DOI: 10.1039/c7cs00601b] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review summarizes the developments in polyatomic reaction dynamics, focusing on reactions of unsaturated hydrocarbons with O-atoms and methane with atoms/radicals.
Collapse
Affiliation(s)
- Huilin Pan
- Institute of Atomic and Molecular Sciences (IAMS)
- Academia Sinica
- Taipei
- Taiwan
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS)
- Academia Sinica
- Taipei
- Taiwan
- Department of Physics
| | - Adriana Caracciolo
- Dipartimento di Chimica
- Biologia e Biotecnologie
- Università degli Studi di Perugia
- 06123 Perugia
- Italy
| | - Piergiorgio Casavecchia
- Dipartimento di Chimica
- Biologia e Biotecnologie
- Università degli Studi di Perugia
- 06123 Perugia
- Italy
| |
Collapse
|
12
|
Zhang J, Gao SB, Wu H, Meng QT. State-to-State Quantum Dynamics of Reactions O((3)P) + HD (v = 0-1, j = 0) → OH+D and OD+H: Reaction Mechanism and Vibrational Excitation. J Phys Chem A 2015; 119:8959-70. [PMID: 26247698 DOI: 10.1021/acs.jpca.5b04255] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Time-dependent quantum wave packet dynamics calculations have been performed in order to characterize the dynamics and mechanism of O((3)P) + HD (v = 0-1, j = 0) → OH+D and OD+H reactive collisions using the adiabatic potential energy surface by Rogers et al. [J. Phys. Chem. A 2000, 104, 2308] Special attention has been paid to the calculations and discussion of the state resolved integral and differential cross sections and the product state distributions. In addition, the intramolecular isotopic branching ratio has been determined. The results revealed that the OD + H is the favored product channel and the product OH has the same quantum number v as the reactant HD. For low collision energy, the product angular distributions concentrate in the backward region being consistent with a rebounding mechanism. In the case of higher collision energy, the stripping collisions with larger impact parameters tend to produce sideways and forward scatterings, especially for the HD vibrationally excited state. The cross section and intramolecular isotopic branching ratio are in agreement with the previous theoretical results. A cartoon depiction collision model is built and works well for our calculation results.
Collapse
Affiliation(s)
- Jing Zhang
- School of Physics and Electronics, Shandong Normal University , Jinan 250014, China.,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dlian 116023, China
| | - Shou-Bao Gao
- School of Physics and Electronics, Shandong Normal University , Jinan 250014, China
| | - Hui Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dlian 116023, China
| | - Qing-Tian Meng
- School of Physics and Electronics, Shandong Normal University , Jinan 250014, China
| |
Collapse
|
13
|
Liu K. Perspective: Vibrational-induced steric effects in bimolecular reactions. J Chem Phys 2015; 142:080901. [DOI: 10.1063/1.4913323] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan
| |
Collapse
|
14
|
Zhang B, Liu K, Czakó G. Correlated Dynamics of the O(3P) + CHD3(v=0) Reaction: A Joint Crossed-Beam and Quasiclassical Trajectory Study. J Phys Chem A 2014; 119:7190-6. [DOI: 10.1021/jp510377k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bailin Zhang
- Institute
of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Kopin Liu
- Institute
of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Gábor Czakó
- Laboratory
of Molecular Structure and Dynamics, Institute of Chemistry, Eötvös University, P.O. Box 32, H-1518 Budapest 112, Hungary
| |
Collapse
|
15
|
Pan H, Yang J, Wang F, Liu K. Imaging the Stereodynamics of Cl + CH4(ν3 = 1): Polarization Dependence on the Rotational Branch and the Hyperfine Depolarization. J Phys Chem Lett 2014; 5:3878-3883. [PMID: 26278763 DOI: 10.1021/jz502088c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The transition state in the Cl + CH4 reaction is of Cl-H-C collinear geometry, which serves as the bottleneck to reaction. When the reactant CH4 is antisymmetrically stretch-excited to ν3 = 1 by absorbing a linearly polarized photon, all four C-H bonds are collectively excited, and any one of the H atoms could be attacked by the Cl atom. At first sight, it is not obvious how an excited spherical-top molecule like CH4 is aligned and what consequences will be on chemical reactivity by polarizing the CH4 reagents. As shown here, an enormous steric effect on reactivity is observed, which depends sensitively on the selected rotational states. By exploiting various rotational branches in optical excitation, we quantify the degree of stereospecificity for a few lowest rovibrational states of the aligned CH4(ν3 = 1) reagents, as well as account for the hyperfine depolarization factor. This information lays the foundation for a full stereorequirement study of the Cl + CH4(ν3 = 1) reaction.
Collapse
Affiliation(s)
- Huilin Pan
- †Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Jiayue Yang
- †Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Fengyan Wang
- †Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Kopin Liu
- †Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
- ‡Department of Physics, National Taiwan University, Taipei, Taiwan 10617
| |
Collapse
|
16
|
Jiang B, Guo H. Mode Specificity, Bond Selectivity, and Product Energy Disposal in X + CH4/CHD3(X=H, F, O(3P), Cl, and OH) Hydrogen Abstraction Reactions: Perspective from Sudden Vector Projection Model. J CHIN CHEM SOC-TAIP 2014. [DOI: 10.1002/jccs.201400158] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
17
|
Yan W, Wang D. Quantum reaction dynamics study of vibrational excitation effects on the Cl+CHD3/CD4→HCl/DCl+CD3 reactions. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.04.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
18
|
|
19
|
Shan X, Remmert SM, Clary DC, Zhang B, Liu K. Crossed-beam and reduced dimensionality studies of the state-to-state integral cross sections of the Cl+HCD3(v)→HCl(v′)+CD3 reaction. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.09.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
20
|
Czakó G, Liu R, Yang M, Bowman JM, Guo H. Quasiclassical Trajectory Studies of the O(3P) + CX4(vk = 0, 1) → OX(v) + CX3(n1n2n3n4) [X = H and D] Reactions on an Ab Initio Potential Energy Surface. J Phys Chem A 2013; 117:6409-20. [DOI: 10.1021/jp4038107] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gábor Czakó
- Laboratory of Molecular Structure
and Dynamics, Institute of Chemistry, Eötvös University, H-1518, Budapest 112, P.O. Box 32, Hungary
| | - Rui Liu
- Key Laboratory of Magnetic Resonance
in Biological Systems, State Key Laboratory of Magnetic Resonance
and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance,
Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People’s Republic
of China
| | - Minghui Yang
- Key Laboratory of Magnetic Resonance
in Biological Systems, State Key Laboratory of Magnetic Resonance
and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance,
Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People’s Republic
of China
| | - Joel M. Bowman
- Cherry L. Emerson
Center for Scientific
Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Hua Guo
- Department of Chemistry and
Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| |
Collapse
|
21
|
Wang F, Liu K. Imaging the Effects of Bend-Excitation in the F + CD4(vb=0,1) → DF(v) + CD3(v2=1,2) Reactions. J Phys Chem A 2013; 117:8536-44. [DOI: 10.1021/jp4014866] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fengyan Wang
- Institute of Atomic
and Molecular
Sciences (IAMS), Academia Sinica, P.O.
Box 23-166, Taipei, Taiwan 10617
- Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Kopin Liu
- Institute of Atomic
and Molecular
Sciences (IAMS), Academia Sinica, P.O.
Box 23-166, Taipei, Taiwan 10617
- Department of Physics, National Taiwan University, Taipei,
Taiwan 10617
| |
Collapse
|
22
|
Zhang B, Liu K, Czakó G, Bowman JM. Translational energy dependence of the Cl + CH4(vb = 0, 1) reactions: a joint crossed-beam and quasiclassical trajectory study. Mol Phys 2012. [DOI: 10.1080/00268976.2012.662600] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
23
|
Revealing the stereospecific chemistry of the reaction of Cl with aligned CHD3(ν1 = 1). Nat Chem 2012; 4:636-41. [DOI: 10.1038/nchem.1383] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 05/17/2012] [Indexed: 11/09/2022]
|
24
|
Liu K. Quantum Dynamical Resonances in Chemical Reactions: From A + BC to Polyatomic Systems. ADVANCES IN CHEMICAL PHYSICS 2012. [DOI: 10.1002/9781118180396.ch1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
25
|
Zhang J, Liu K. Imaging the Reaction Dynamics of O(3P)+CH4→OH+CH3. Chem Asian J 2011; 6:3132-6. [DOI: 10.1002/asia.201100414] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Indexed: 11/06/2022]
|
26
|
Remmert SM, Banks ST, Harvey JN, Orr-Ewing AJ, Clary DC. Reduced dimensionality spin-orbit dynamics of CH3 + HCl ⇌ CH4 + Cl on ab initio surfaces. J Chem Phys 2011; 134:204311. [DOI: 10.1063/1.3592732] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
|
27
|
Wang F, Lin JS, Liu K. Steric Control of the Reaction of CH Stretch–Excited CHD
3
with Chlorine Atom. Science 2011; 331:900-3. [DOI: 10.1126/science.1199771] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Fengyan Wang
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617
| | - Jui-San Lin
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617
- Department of Physics, National Taiwan University, Taipei, Taiwan 10617 and Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 300
| |
Collapse
|
28
|
Greaves SJ, Rose RA, Abou-Chahine F, Glowacki DR, Troya D, Orr-Ewing AJ. Quasi-classical trajectory study of the dynamics of the Cl + CH4→ HCl + CH3 reaction. Phys Chem Chem Phys 2011; 13:11438-45. [DOI: 10.1039/c0cp02694h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
29
|
Kawamata H, Liu K. Imaging the nature of the mode-specific chemistry in the reaction of Cl atom with antisymmetric stretch-excited CH4. J Chem Phys 2010; 133:124304. [DOI: 10.1063/1.3482628] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
30
|
Greaves SJ, Rose RA, Orr-Ewing AJ. Velocity map imaging of the dynamics of bimolecular chemical reactions. Phys Chem Chem Phys 2010; 12:9129-43. [PMID: 20448868 DOI: 10.1039/c001233e] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The experimental technique of velocity map imaging (VMI) enables measurements to be made of the dynamics of chemical reactions that are providing unprecedented insights about reactive scattering. This perspective article illustrates how VMI, in combination with crossed-molecular beam, dual-beam or photo-initiated (Photoloc) methods, can reveal correlated information on the vibrational quantum states populated in the two products of a reaction, and the angular scattering of products (the differential cross section) formed in specific rotational and vibrational levels. Reactions studied by VMI techniques are being extended to those of polyatomic molecules or radicals, and of molecular ions. Subtle quantum-mechanical effects in bimolecular reactions can provide distinct signatures in the velocity map images, and are exemplified here by non-adiabatic dynamics on coupled potential energy surfaces, and by experimental evidence for scattering resonances.
Collapse
Affiliation(s)
- Stuart J Greaves
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | | | | |
Collapse
|
31
|
Rose RA, Greaves SJ, Orr-Ewing AJ. Velocity map imaging of the dynamics of the CH3+ HCl → CH4+ Cl reaction using a dual molecular beam method. Mol Phys 2010. [DOI: 10.1080/00268971003610234] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
32
|
|
33
|
Wu G, Zhang W, Pan H, Shuai Q, Yang J, Jiang B, Dai D, Yang X. Crossed molecular beam ion-imaging study of the Cl + SiH4→ HCl + SiH3 reaction: product vibrational state-to-state correlation. Phys Chem Chem Phys 2010; 12:9469-74. [DOI: 10.1039/b927455c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
34
|
Kaiser RI, Maksyutenko P, Ennis C, Zhang F, Gu X, Krishtal SP, Mebel AM, Kostko O, Ahmed M. Untangling the chemical evolution of Titan's atmosphere and surface–from homogeneous to heterogeneous chemistry. Faraday Discuss 2010; 147:429-78; discussion 527-52. [DOI: 10.1039/c003599h] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
35
|
Wang F, Liu K. Enlarging the reactive cone of acceptance by exciting the C–H bond in the O(3P) + CHD3 reaction. Chem Sci 2010. [DOI: 10.1039/c0sc00186d] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
36
|
Chichinin AI, Gericke KH, Kauczok S, Maul C. Imaging chemical reactions – 3D velocity mapping. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350903235045] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
37
|
Huarte-Larrañaga F, Manthe U. Thermal Rate Constants for Polyatomic Reactions: First Principles Quantum Theory. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zpch.2007.221.2.171] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The truly accurate knowledge of molecular dynamics phenomena is generally achieved through a combination of detailed experiments and first principle theory. The complexity of such a level of description had until recently restricted accurate studies to rather small systems. However, the sophistication of theoretical methods and massive technological developments have provided remarkable progress in the detailed knowledge of reactive events during the past three decades. Moreover, significant progress towards the detailed understanding of polyatomic reaction has been made in recent years. Detailed experimental and accurate theoretical studies of reactions involving more than only three or four atoms are becoming increasingly available. In this work, aspects of the theoretical work aiming at the accurate description of polyatomic reactions are reviewed.
The present article focuses on the development of the first principle theory of reaction rates. It reviews theoretical developments and benchmark applications to reactions as CH4 + H → CH3 + H2 and CH4 + O → CH3 + OH. The importance of quantum effects for the thermal rate constants in different temperature regimes is discussed in detail. The accuracy of the classical transition state theory and of different approximate quantum theories is investigated in detail. A quantum transition state concept which facilitates accurate reaction rate calculations for polyatomic reaction is described. Benchmark results for the CH4 + H → CH3 + H2 reaction are shown which demonstrate that the accuracy of thermal rate constants calculated by first principle theory can rival the accuracy of available experimental data. The perspectives offered by these developments are discussed.
Collapse
|
38
|
Taylor MS, Ivanic SA, Wood GPF, Easton CJ, Bacskay GB, Radom L. Hydrogen Abstraction by Chlorine Atom from Small Organic Molecules Containing Amino Acid Functionalities: An Assessment of Theoretical Procedures. J Phys Chem A 2009; 113:11817-32. [DOI: 10.1021/jp9029437] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Mark S. Taylor
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia, and Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| | - Sandra A. Ivanic
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia, and Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| | - Geoffrey P. F. Wood
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia, and Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| | - Christopher J. Easton
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia, and Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| | - George B. Bacskay
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia, and Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| | - Leo Radom
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia, and Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
| |
Collapse
|
39
|
Riedel J, Yan S, Liu K. Mode Specificity in Reactions of Cl with CH2 Stretch-Excited CH2D2(υ1, υ6 = 1). J Phys Chem A 2009; 113:14270-6. [DOI: 10.1021/jp902629h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Jens Riedel
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Shannon Yan
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| |
Collapse
|
40
|
Riedel J, Liu K. Uncovering a Spectrally Hidden REMPI Band of CD3 by Ion Imaging Spectroscopy of the Products of the Cl + CHD3(1131) Reaction. J Phys Chem A 2009; 113:4249-54. [DOI: 10.1021/jp810802g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jens Riedel
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, Taiwan 10617
| |
Collapse
|
41
|
Modified potential energy surface and time-dependent wave packet dynamics study for Cl+CH4→HCl+CH3 reaction. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2008.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
42
|
Abstract
We report a comprehensive study of the quantum-state correlation property of product pairs from reactions of chlorine atoms with both the ground-state and the CH stretch-excited CHD(3). In light of available ab initio theoretical results, this set of experimental data provides a conceptual framework to visualize the energy-flow pattern along the reaction path, to classify the activity of different vibrational modes in a reactive encounter, to gain deeper insight into the concept of vibrational adiabaticity, and to elucidate the intermode coupling in the transition-state region. This exploratory approach not only opens up an avenue to understand polyatomic reaction dynamics, even for motions at the molecular level in the fleeting transition-state region, but it also leads to a generalization of Polanyi's rules to reactions involving a polyatomic molecule.
Collapse
|
43
|
Retail B, Rose RA, Pearce JK, Greaves SJ, Orr-Ewing AJ. The dynamics of reaction of Cl atoms with tetramethylsilane. Phys Chem Chem Phys 2008; 10:1675-80. [DOI: 10.1039/b716512a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
44
|
Kawamata H, Tauro S, Liu K. Unravelling the reactivity of antisymmetric stretch-excited CH4 with Cl by-product pair-correlation measurements. Phys Chem Chem Phys 2008; 10:4378-82. [DOI: 10.1039/b809209e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
45
|
Nyman G, Zhou J, Zhang B, Liu K. Crossed-Beam and Quantum Dynamics Studies of the Reaction Cl + CHD3. Isr J Chem 2007. [DOI: 10.1560/ijc.47.1.1] [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]
|
46
|
Espinosa-García J. Role of the C-H stretch mode excitation in the dynamics of the Cl + CHD3 reaction: a quasi-classical trajectory calculation. J Phys Chem A 2007; 111:9654-61. [PMID: 17824676 DOI: 10.1021/jp073549u] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To analyze the effect of the C-H stretch mode excitation on the dynamics of the Cl + CHD3 gas-phase abstraction reaction, an exhaustive state-to-state dynamics study was performed. This reaction can evolve along two channels: H-abstraction, CD3 + ClH, and D-abstraction, CHD2 + ClD. On an analytical potential energy surface constructed previously by our group, named PES-2005, quasi-classical trajectory calculations were performed at a collision energy of 0.18 eV, including corrections to avoid zero-point energy leakage along the trajectories. First, strong coupling between different vibrational modes in the entry valley was observed; i.e., the reaction is vibrationally nonadiabatic. Second, for the ground-state CHD3(nu=0) reaction, the diatomic fragments appeared in their ground states, and the H- and D-abstraction reactions showed similar reactivities. However, when the reactivity per atom is considered, the H is three times more reactive than the D atom. Third, when the C-H stretch mode is excited by one quantum, CHD3(nu1=1), the H-abstraction is strongly favored, and the C-H stretch excitation is maintained in the product CHD2(nu1=1) + ClD channel; i.e., the reaction shows mode selectivity, reproducing the experimental evidence, and also the reactivity of the vibrational ground state is increased, in agreement with experiment. Fourth, the state-to-state angular distributions of the CD3 and CHD2 products showed the products to be practically sideways for the reactant ground state, while the C-H excitation yielded a more forward scattering, reproducing the experimental data. The role of the zero-point energy correction was also analyzed, and we find that the dynamics results are very sensitive on how the ZPE issue is treated. Finally, a comparison is made with the similar H + CHD3(nu1=0,1) and Cl + CH4(nu1=0,1) reactions.
Collapse
Affiliation(s)
- J Espinosa-García
- Departamento de Química Física, Universidad de Extremadura, 06071 Badajoz, Spain. joaquin.unex.es
| |
Collapse
|
47
|
Yan S, Liu K. Pair-correlated Dynamics of Cl+CHD3(v1=1) Reaction: Effects of Probe Laser Frequency. CHINESE J CHEM PHYS 2007. [DOI: 10.1088/1674-0068/20/04/333-338] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
48
|
Zhang B, Yan S, Liu K. Unraveling Multicomponent Images by Extended Cross Correlation Analysis. J Phys Chem A 2007; 111:9263-8. [PMID: 17636971 DOI: 10.1021/jp072916z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the course of studying the reaction dynamics of F + CH(2)D(2) --> HF + CHD(2), several small features in the (2+1) REMPI spectra of the CHD(2) product were observed. Using the technique of imaging spectroscopy, those new features were identified and assigned to the 2(1)(1), 3(1)(1), and 5(1)(1) bands. The ion velocity-mapped images acquired for those features, however, displayed severe overlaps with each other, rendering data analysis difficult. The extended cross correlation method was then applied for the first time in analyzing the ion images and successfully extracted the genuine pattern of each entangled component, which in turn enables us to focus on the dynamics information embedded in the multicomponent images.
Collapse
Affiliation(s)
- Bailin Zhang
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166 Taipei, Taiwan 10617
| | | | | |
Collapse
|
49
|
Yan S, Wu YT, Zhang B, Yue XF, Liu K. Do Vibrational Excitations of CHD3 Preferentially Promote Reactivity Toward the Chlorine Atom? Science 2007; 316:1723-6. [PMID: 17588925 DOI: 10.1126/science.1142313] [Citation(s) in RCA: 237] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The influence of vibrational excitation on chemical reaction dynamics is well understood in triatomic reactions, but the multiple modes in larger systems complicate efforts toward the validation of a predictive framework. Although recent experiments support selective vibrational enhancements of reactivities, such studies generally do not properly account for the differing amounts of total energy deposited by the excitation of different modes. By precise tuning of translational energies, we measured the relative efficiencies of vibration and translation in promoting the gas-phase reaction of CHD3 with the Cl atom to form HCl and CD3. Unexpectedly, we observed that C-H stretch excitation is no more effective than an equivalent amount of translational energy in raising the overall reaction efficiency; CD3 bend excitation is only slightly more effective. However, vibrational excitation does have a strong impact on product state and angular distributions, with C-H stretch-excited reactants leading to predominantly forward-scattered, vibrationally excited HCl.
Collapse
Affiliation(s)
- Shannon Yan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Post Office Box 23-166, Taipei, Taiwan 10617
| | | | | | | | | |
Collapse
|
50
|
Abstract
The vast majority of chemical reactions involve polyatomic species as reactants and/or products. The added degree of complexity offers opportunities to address dynamical questions other than those already encountered in a typical atom + diatom reaction. Product pair correlation is one of them. This article introduces the basic concept, outlines the experimental approach we developed and then highlights some of the applications to bimolecular reaction dynamics. Particular emphasis is placed on the information contents and unique insights gained from this type of measurements, which otherwise would have been lost by the conventional approach.
Collapse
Affiliation(s)
- Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, P.O. Box 23-166, Taipei, 10617, Taiwan
| |
Collapse
|