1
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Aardema M, Fast M, Meas B, North SW. Rotational Distributions and Imaging of Singlet O 2 Following Spin-Forbidden Photodissociation of O 3. J Phys Chem A 2023; 127:7101-7114. [PMID: 37540577 PMCID: PMC10863062 DOI: 10.1021/acs.jpca.3c02736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/14/2023] [Indexed: 08/06/2023]
Abstract
We report REMPI spectra and velocity-mapped ion images of the O2(a1Δg) and (b1Σg+) fragments arising from the spin-forbidden photodissociation of O3 near 320 and 330 nm. The O2(a1Δg, v = 0) REMPI spectrum following a 320 nm dissociation shows enhanced peak intensity for the odd rotational states relative to the even states, which is the opposite of the trend observed by Gunthardt et al. ( J. Chem. Phys. 2019, 151, 224302) for spin-allowed dissociation at 266 nm but is consistent with the couplings between the B state and 3A' and 3A″ states calculated by Grebenshchikov and Rosenwaks ( J. Phys. Chem. A 2010, 114, 9809-9819). There are no significant differences between the ion image angular distributions of fragments in odd and even rotational states, which indicates a cold distribution of O3 and supports the explanation that the alternation in peak intensities results from a difference in the couplings. Quantitative analysis of the image angular distributions was limited due to the single laser polarization geometry accessible in one-color experiments. Radial distributions of the 320 nm images indicate a broad rotational distribution, evidenced in bimodal speed distributions with peaks corresponding to both high (j = 35-43) and low (j = 17-20) rotational states. The REMPI spectrum of O2(a1Δg) near 330 nm was collected, and while quantitative population analysis is difficult because of the perturbed resonant state, the spectrum clearly supports a broad rotational distribution as well, consistent with the images collected at 320 nm. A 2D-REMPI spectrum was collected following dissociation of O3 near 330 nm, which showed evidence of contributions from O2 fragments in both the a1Δg and b1Σg+ states. The rotational distribution for the O2(b1Σg+, v = 0) product peaks at j = 32 and is narrower than that of the O2(a1Δg) fragment, consistent with distributions reported by O'Keeffe et al. at longer dissociation wavelengths ( J. Chem. Phys. 2002, 117, 8705-8709). At smaller radii in the 2D-REMPI spectrum, there is additional signal assigned to v = 1-4 of O2(b1Σg+), with rotational distributions similar to v = 0. The vibrational distribution of the O2(b1Σg+) fragment peaks at v = 0, with populations monotonically decreasing with increasing vibrational state. Ion image angular distributions of the O2(b1Σg+) fragment and the corresponding anisotropy parameters are also reported.
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Affiliation(s)
- Megan
N. Aardema
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Megan Fast
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Benjamen Meas
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Simon W. North
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
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2
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Shuber NJ, Tabor DP, North SW. Theoretical Investigation of the Ground State Dissociation Pathways of CH2NO2. Chem Phys 2023. [DOI: 10.1016/j.chemphys.2023.111823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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3
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Aardema MN, McBane GC, North SW. Ozone Photodissociation in the Singlet Channel at 226 nm. J Phys Chem A 2022; 126:6898-6907. [PMID: 36129835 DOI: 10.1021/acs.jpca.2c04832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the rotational state distribution and vector correlations of the O2(a 1Δg, v = 0) fragments arising from the 226 nm photodissociation of jet-cooled O3. Consistent with previously reported trends, the rotational distribution is shifted to higher rotational states with decreasing wavelength. We observe highly suppressed odd rotational state populations due to a strong Λ-doublet propensity. The measured rotational distribution is in agreement with classical trajectory calculations for the v = 0 products, although the distribution is slightly narrower than predicted. The spatial anisotropy follows the previously observed trend of decreasing β with increasing photon energy with β = 0.72 ± 0.14 for v = 0, j = 38. As expected for a triatomic molecule, the v-j correlation is consistent with v perpendicular to j, but the measured correlation is nonlimiting due, in part, to rotational and translational depolarization. The j-dependent line width of the O2(a 1Δg) REMPI spectrum is also discussed in connection with the lifetime of the resonant O2(d 1Πg) state due to predissociation via the II 1Πg valence state.
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Affiliation(s)
- Megan N Aardema
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - George C McBane
- Department of Chemistry, Grand Valley State University, Allendale, Michigan 49401, United States
| | - Simon W North
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
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4
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Analysis of the roaming trajectories from the dynamic and kinematic perspectives – A representative study of triatomic systems. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Palazzetti F, Tsai PY. Photodissociation Dynamics of CO-Forming Channels on the Ground-State Surface of Methyl Formate at 248 nm: Direct Dynamics Study and Assessment of Generalized Multicenter Impulsive Models. J Phys Chem A 2021; 125:1198-1220. [PMID: 33507759 DOI: 10.1021/acs.jpca.0c10464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The photodissociation dynamics of methyl formate in the electronic ground state S0, initiated by a 248 nm-wavelength laser, is studied by direct dynamics simulations. We analyze five channels, where four of them have as products CH3OH + CO, one leading to the formation of three fragments, H2CO + H2 + CO, and a channel characterized by a roaming transition state. The analysis of energy distribution among the degrees of freedom of the product and the comparison with experimental results previously published by other groups provide the ingredients to distinguish the examined dissociation pathways. The interpretation of the results proves that the characterization of dissociation mechanisms must rely on a dynamics approach involving multiple electronic states, including considerations on the features of the S1/S0 conical intersection. Here, we also assess the generalized multicenter impulsive model, GMCIM, that has been designed for dissociation processes with exit barriers, and the energy distribution in the products is predicted on the basis of information from the saddle points and the intrinsic reaction coordinates. Main features, advantages, limits, and future perspectives of the method are reported and discussed.
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Affiliation(s)
- Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia 06123, Italy
| | - Po-Yu Tsai
- Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan
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6
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Gunthardt CE, Aardema MN, Hall GE, North SW. Evidence for lambda doublet propensity in the UV photodissociation of ozone. J Chem Phys 2019; 151:224302. [PMID: 31837678 DOI: 10.1063/1.5131504] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photodissociation of O3 at 266 nm has been studied using velocity mapped ion imaging. We report temperature-dependent vector correlations for the O2(a1Δg, v = 0, j = 18-20) fragments at molecular beam temperatures of 70 K, 115 K, and 170 K. Both the fragment spatial anisotropy and the v-j correlations are found to be increasingly depolarized with increasing beam temperature. At all temperatures, the v-j correlations for the j = 19 state were shown to be reduced compared to those of j = 18 and 20, while no such odd/even rotational state difference was observed for the spatial anisotropy, consistent with previous measurements. We find that temperature-dependent differences in the populations and v-j correlations between the odd and even rotational states can be explained by a Λ-doublet propensity model. Although symmetry conservation should lead to formation of only the A' Λ-doublet component, and only even rotational states, out-of-plane rotation of the parent molecule breaks the planar symmetry and permits the formation of the A″ Λ-doublet component and odd rotational states. A simple classical model to treat the effect of parent rotation on the v-j correlation and the odd/even rotational population alternation reproduces both the current measurements and previously reported rotational distributions, suggesting that the "odd" behavior originates from a Λ-doublet propensity, and not from a mass independent curve crossing effect, as previously proposed.
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Affiliation(s)
- Carolyn E Gunthardt
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
| | - Megan N Aardema
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
| | - Gregory E Hall
- Chemistry Division, Brookhaven National Laboratory P.O. Box 5000 Upton, New York 11973-5000, USA
| | - Simon W North
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
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7
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Blackshaw KJ, Quartey NK, Korb RT, Hood DJ, Hettwer CD, Kidwell NM. Imaging the nonreactive collisional quenching dynamics of NO (A 2Σ +) radicals with O 2 (X 3Σ g -). J Chem Phys 2019; 151:104304. [PMID: 31521090 DOI: 10.1063/1.5109112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nitric oxide (NO) radicals are ubiquitous chemical intermediates present in the atmosphere and in combustion processes, where laser-induced fluorescence is extensively used on the NO (A2Σ+ ← X2Π) band to report on fuel-burning properties. However, accurate fluorescence quantum yields and NO concentration measurements are impeded by electronic quenching of NO (A2Σ+) to NO (X2Π) with colliding atomic and molecular species. To improve predictive combustion models and develop a molecular-level understanding of NO (A2Σ+) quenching, we report the velocity map ion images and product state distributions of NO (X2Π, v″ = 0, J″, Fn, Λ) following nonreactive collisional quenching of NO (A2Σ+) with molecular oxygen, O2 (X3Σg -). A novel dual-flow pulse valve nozzle is constructed and implemented to carry out the NO (A2Σ+) electronic quenching studies and to limit NO2 formation. The isotropic ion images reveal that the NO-O2 system evolves through a long-lived NO3 collision complex prior to formation of products. Furthermore, the corresponding total kinetic energy release distributions support that O2 collision coproducts are formed primarily in the c1Σu - electronic state with NO (X2Π, v″ = 0, J″, Fn, Λ). The product state distributions also indicate that NO (X2Π) is generated with a propensity to occupy the Π(A″) Λ-doublet state, which is consistent with the NO π* orbital aligned perpendicular to nuclear rotation. The deviations between experimental results and statistical phase space theory simulations illustrate the key role that the conical intersection plays in the quenching dynamics to funnel population to product rovibronic levels.
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Affiliation(s)
- K Jacob Blackshaw
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Naa-Kwarley Quartey
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Robert T Korb
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - David J Hood
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Christian D Hettwer
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
| | - Nathanael M Kidwell
- Department of Chemistry, The College of William and Mary, Williamsburg, Virginia 23187-8795, USA
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8
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Asatryan R, Pal Y, Hachmann J, Ruckenstein E. Roaming-like Mechanism for Dehydration of Diol Radicals. J Phys Chem A 2018; 122:9738-9754. [DOI: 10.1021/acs.jpca.8b08690] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rubik Asatryan
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Yudhajit Pal
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
- Computational and Data-Enabled Science and Engineering Graduate Program, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Johannes Hachmann
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
- New York State Center of Excellence in Materials Informatics, Buffalo, New York 14203, United States
- Computational and Data-Enabled Science and Engineering Graduate Program, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Eli Ruckenstein
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
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9
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Suits AG. Invited Review Article: Photofragment imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:111101. [PMID: 30501356 DOI: 10.1063/1.5045325] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/25/2018] [Indexed: 06/09/2023]
Abstract
Photodissociation studies in molecular beams that employ position-sensitive particle detection to map product recoil velocities emerged thirty years ago and continue to evolve with new laser and detector technologies. These powerful methods allow application of tunable laser detection of single product quantum states, simultaneous measurement of velocity and angular momentum polarization, measurement of joint product state distributions for the detected and undetected products, coincident detection of multiple product channels, and application to radicals and ions as well as closed-shell molecules. These studies have permitted deep investigation of photochemical dynamics for a broad range of systems, revealed new reaction mechanisms, and addressed problems of practical importance in atmospheric, combustion, and interstellar chemistry. This review presents an historical overview, a detailed technical account of the range of methods employed, and selected experimental highlights illustrating the capabilities of the method.
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Affiliation(s)
- Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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10
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Warter ML, Gunthardt CE, Wei W, McBane GC, North SW. Nascent O 2 ( a 1Δ g, v = 0, 1) rotational distributions from the photodissociation of jet-cooled O 3 in the Hartley band. J Chem Phys 2018; 149:134309. [PMID: 30292221 DOI: 10.1063/1.5051540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report rotational distributions for the O2 (a 1Δg) fragment from the photodissociation of jet-cooled O3 at 248, 266, and 282 nm. The rotational distributions show a population alternation that favors the even states, as previously reported for a 300 K sample by Valentini et al. [J. Chem. Phys. 86, 6745 (1987)]. The alternation from the jet-cooled precursor is much stronger than that observed by Valentini et al. and in contrast to their observations does not depend strongly on the O2 (a 1Δg) vibrational state or photolysis wavelength. The odd/even alternation diminishes substantially when the ozone beam temperature is increased from 60 to 200 K, confirming its dependence on parent internal energy. The magnitude of the even/odd alternation in product rotational states from the cold ozone sample, its temperature dependence, and other experimental and theoretical evidence reported since 1987 suggest that the alternation originates from a Λ-doublet propensity and not from a mass independent curve crossing effect, as previously proposed.
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Affiliation(s)
- Michelle L Warter
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
| | - Carolyn E Gunthardt
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
| | - Wei Wei
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
| | - George C McBane
- Department of Chemistry, Grand Valley State University, Allendale, Michigan 49401, USA
| | - Simon W North
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, USA
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11
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Lin KC, Tsai PY, Chao MH, Nakamura M, Kasai T, Lombardi A, Palazzetti F, Aquilanti V. Roaming signature in photodissociation of carbonyl compounds. INT REV PHYS CHEM 2018. [DOI: 10.1080/0144235x.2018.1488951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan (ROC)
| | - Po-Yu Tsai
- Department of Chemistry, National Chung-Hsing University, Taichung, Taiwan (ROC)
| | - Meng-Hsuan Chao
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
| | - Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
- Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Andrea Lombardi
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Consortium for Computational Molecular and Materials Sciences (CMS)2, Perugia, Italy
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Scuola Normale Superiore di Pisa, Pisa, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome, Italy
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12
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Tsai PY. A generalized unimolecular impulsive model for curved reaction path. J Chem Phys 2018; 148:234101. [PMID: 29935512 DOI: 10.1063/1.5030488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
This work aims to introduce a generalized impulsive model for unimolecular dissociation processes. This model allows us to take into account the curvature of the reaction path explicitly. It is a generalization of the previously developed multi-center impulsive model [P.-Y. Tsai and K.-C. Lin, J. Phys. Chem. A 119, 29 (2015)]. Several limitations of conventional impulsive models are eliminated by this study: (1) Unlike conventional impulsive models, in which a single molecular geometry is responsible for the impulse determination, the gradients on the whole dissociation path are taken into account. The model can treat dissociation pathways with large curvatures and loose saddle points. (2) The method can describe the vibrational excitation of polyatomic fragments due to the bond formation by multi-center impulse. (3) The available energy in conventional impulsive models is separated into uncoupled statistical and impulsive energy reservoirs, while the interplay between these reservoirs is allowed in the new model. (4) The quantum state correlation between fragments can be preserved in analysis. Dissociations of several molecular systems including the roaming pathways of formaldehyde, nitrate radical, acetaldehyde, and glyoxal are chosen as benchmarks. The predicted photofragment energy and vector distributions are consistent with the experimental results reported previously. In these examples, the capability of the new model to treat the curved dissociation path, loose saddle points, polyatomic fragments, and multiple-body dissociation is verified. As a cheaper computational tool with respect to ab initio on-the-fly direct dynamic simulations, this model can provide detailed information on the energy disposal, quantum state correlation, and stereodynamics in unimolecular dissociation processes.
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Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan
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13
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Chen LW, Hung CM, Matsui H, Lee YP. New experimental evidence to support roaming in the reaction Cl + isobutene (i-C 4H 8). Sci Rep 2017; 7:40105. [PMID: 28079173 PMCID: PMC5228202 DOI: 10.1038/srep40105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 11/30/2016] [Indexed: 12/05/2022] Open
Abstract
The reaction Cl + isobutene (i-C4H8) was reported by Suits et al. to proceed via, in addition to abstraction, an addition-elimination path following a roaming excursion of Cl; a near-zero translational energy release and an isotropic angular distribution observed at a small collision energy characterized this mechanism. We employed a new experimental method to further characterize this roaming mechanism through observation of the internal distribution of HCl (v, J) and their temporal behavior upon irradiation of a mixture of Cl2C2O2 and i-C4H8 in He or Ar buffer gas. With 1–3 Torr buffer gas added to approach the condition of small collision energy, the intensities of emission of HCl (v = 1, 2) and the HCl production rates increased significantly; Ar shows a more significant effect than He because Ar quenches Cl more efficiently to reduce the collisional energy and facilitate the roaming path. According to kinetic modeling, the rate of addition-elimination (roaming) increased from kE ≈ 2 × 105 s−1 when little buffer gas was present to ~1.9 × 106 s−1 when 2–3 Torr of Ar was added, and the branching ratio for formation of [HCl (v = 2)]/[HCl (v = 1)] increased from 0.02 ± 0.01 for abstraction to 0.06 ± 0.01 for roaming.
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Affiliation(s)
- Li-Wei Chen
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - Ching-Ming Hung
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - Hiroyuki Matsui
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan.,Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
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14
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Yosa Reyes J, Nagy T, Meuwly M. Competitive reaction pathways in vibrationally induced photodissociation of H2SO4. Phys Chem Chem Phys 2015; 16:18533-44. [PMID: 25072517 DOI: 10.1039/c4cp01832j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vibrationally induced photodissociation of sulfuric acid into H2O + SO3 is investigated based on reactive molecular dynamics (MD) simulations. Multisurface adiabatic reactive MD simulations allow us to follow both, H-transfer and water elimination after excitation of the ν9 OH-stretching mode. Analysis of several thousand trajectories finds that the H2O and SO3 fragments have distinct final state distributions with respect to translational, rotational, and vibrational degrees of freedom. Rotational distributions peak at quantum numbers j ≤ 5 for water and j ≈ 60 for SO3. The final state distributions should be useful in identifying products in forthcoming experiments. Based on the MD trajectories, a kinetic scheme has been developed which is able to explain most of the trajectory data and suggests that IVR is very rapid. Typical lifetimes of the excited complex range from several 10 picoseconds to hundreds of nanoseconds, depending on the excitation level. Including temperature and pressure profiles characteristic for the stratosphere in the kinetic model shows that excitations higher than ν9 = 4 can significantly contribute to the photolysis rate. This extends and specifies earlier work in that multi-level modeling is required to understand the significance of vibrationally induced decomposition pathways of sulfuric acid in the middle atmosphere.
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Affiliation(s)
- Juvenal Yosa Reyes
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland. m.meuwly-at-unibas.ch
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15
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Maeda S, Taketsugu T, Ohno K, Morokuma K. From Roaming Atoms to Hopping Surfaces: Mapping Out Global Reaction Routes in Photochemistry. J Am Chem Soc 2015; 137:3433-45. [DOI: 10.1021/ja512394y] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Satoshi Maeda
- Department
of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Tetsuya Taketsugu
- Department
of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Koichi Ohno
- Graduate
School of Science, Tohoku University, Sendai 980-8578, Japan
- Institute for Quantum Chemical Exploration, Tokyo 108-0022, Japan
| | - Keiji Morokuma
- Fukui
Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
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16
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Maeda S, Taketsugu T, Morokuma K, Ohno K. Anharmonic Downward Distortion Following for Automated Exploration of Quantum Chemical Potential Energy Surfaces. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2014. [DOI: 10.1246/bcsj.20140189] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Satoshi Maeda
- Department of Chemistry, Faculty of Science, Hokkaido University
| | | | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry, Kyoto University
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University
| | - Koichi Ohno
- Graduate School of Science, Tohoku University
- Institute for Quantum Chemical Exploration
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17
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Fernando R, Dey A, Broderick BM, Fu B, Homayoon Z, Bowman JM, Suits AG. Visible/Infrared Dissociation of NO3: Roaming in the Dark or Roaming on the Ground? J Phys Chem A 2014; 119:7163-8. [DOI: 10.1021/jp509902d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ravin Fernando
- Department
of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Arghya Dey
- Department
of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Bernadette M. Broderick
- Department
of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Bina Fu
- State Key Laboratory
of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Zahra Homayoon
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, 201 Dowman Drive, Atlanta, Georgia 30322, United States
| | - Joel M. Bowman
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, 201 Dowman Drive, Atlanta, Georgia 30322, United States
| | - Arthur G. Suits
- Department
of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
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18
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Lee KLK, Quinn MS, Maccarone AT, Nauta K, Houston PL, Reid SA, Jordan MJT, Kable SH. Two roaming pathways in the photolysis of CH3CHO between 328 and 308 nm. Chem Sci 2014. [DOI: 10.1039/c4sc02266a] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We attribute the two product-state distributions previously seen in CH3CHO photodissociation to CH3-roaming and H-roaming, unifying all previous experimental results.
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Affiliation(s)
- Kin Long K. Lee
- School of Chemistry
- University of New South Wales
- Kensington, Australia
| | - Mitchell S. Quinn
- School of Chemistry
- University of New South Wales
- Kensington, Australia
| | | | - Klaas Nauta
- School of Chemistry
- University of New South Wales
- Kensington, Australia
| | - Paul L. Houston
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta, USA
| | - Scott A. Reid
- School of Chemistry
- University of Sydney
- Sydney, Australia
| | | | - Scott H. Kable
- School of Chemistry
- University of New South Wales
- Kensington, Australia
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19
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Andrews DU, Kable SH, Jordan MJT. A Phase Space Theory for Roaming Reactions. J Phys Chem A 2013; 117:7631-42. [DOI: 10.1021/jp405582z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Scott H. Kable
- School of
Chemistry, University of Sydney, NSW 2006,
Australia
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20
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Fu B, Zhang DH, Bowman JM. Quasiclassical trajectory studies of 18O(3P) + NO2 isotope exchange and reaction to O2 + NO on D0 and D1 potentials. J Chem Phys 2013; 139:024303. [PMID: 23862939 DOI: 10.1063/1.4812802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report quasiclassical trajectory calculations for the bimolecular reaction (18)O((3)P) + NO2 on the recent potential energy surfaces of the ground (D0) and first excited (D1) states of NO3 [B. Fu, J. M. Bowman, H. Xiao, S. Maeda, and K. Morokuma, J. Chem. Theory. Comput. 9, 893 (2013)]. The branching ratio of isotope exchange versus O2 + NO formation, as well as the product angular distributions and energy and rovibrational state distributions are presented. The calculations are done at the collision energy of relevance to recent crossed beam experiments [K. A. Mar, A. L. Van Wyngarden, C.-W. Liang, Y. T. Lee, J. J. Lin, and K. A. Boering, J. Chem. Phys. 137, 044302 (2012)]. Very good agreement is achieved between the current calculations and these experiments for the branching ratio and final translational energy and angular distributions of isotope exchange products (16)O((3)P) + NO2 and O2 + NO formation products. The reactant (18)O atom results in (18)O(16)O but not N(18)O for the O2 + NO formation product channel, consistent with the experiment. In addition, the detailed vibrational and rotational state information of diatomic molecules calculated currently for the (34)O2 + NO formation channel on D0 and D1 states are in qualitative agreement with the previous experimental and theoretical results of the photodissociation of NO3 and are consistent with older thermal bimolecular kinetics measurements.
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Affiliation(s)
- Bina Fu
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.
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21
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Xiao H, Maeda S, Morokuma K. Theoretical Study on the Photodissociation of Methylamine Involving S1, T1, and S0 States. J Phys Chem A 2013; 117:5757-64. [DOI: 10.1021/jp4042952] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hongyan Xiao
- Fukui Institute
for Fundamental
Chemistry, Kyoto University, 34-4 Takano
Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
- Key Laboratory of Photochemical
Conversion and Optoelectronic Materials, Technical Institute of Physics
and Chemistry, Chinese Academy of Sciences, Beijing 100190, People’s Republic of China
| | - Satoshi Maeda
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Keiji Morokuma
- Fukui Institute
for Fundamental
Chemistry, Kyoto University, 34-4 Takano
Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
- Cherry L. Emerson Center for
Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322,
United States
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22
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Fu B, Bowman JM, Xiao H, Maeda S, Morokuma K. Quasiclassical Trajectory Studies of the Photodissociation Dynamics of NO3 from the D0 and D1 Potential Energy Surfaces. J Chem Theory Comput 2013; 9:893-900. [DOI: 10.1021/ct3009792] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bina Fu
- Department
of Chemistry and Cherry L. Emerson Center for Scientific
Computation, Emory University, Atlanta,
Georgia 30322, United States
- State Key Laboratory of Molecular
Reaction Dynamics and Center for Theoretical and Computational Chemistry,
Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People’s Republic
of China
| | - Joel M. Bowman
- Department
of Chemistry and Cherry L. Emerson Center for Scientific
Computation, Emory University, Atlanta,
Georgia 30322, United States
| | - Hongyan Xiao
- Fukui Institute
for Fundamental
Chemistry, Kyoto University, Kyoto 606-8103,
Japan
| | - Satoshi Maeda
- Department
of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Keiji Morokuma
- Department
of Chemistry and Cherry L. Emerson Center for Scientific
Computation, Emory University, Atlanta,
Georgia 30322, United States
- Fukui Institute
for Fundamental
Chemistry, Kyoto University, Kyoto 606-8103,
Japan
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23
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Exploring Multiple Potential Energy Surfaces: Photochemistry of Small Carbonyl Compounds. ACTA ACUST UNITED AC 2012. [DOI: 10.1155/2012/268124] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In theoretical studies of chemical reactions involving multiple potential energy surfaces (PESs) such as photochemical reactions, seams of intersection among the PESs often complicate the analysis. In this paper, we review our recipe for exploring multiple PESs by using an automated reaction path search method which has previously been applied to single PESs. Although any such methods for single PESs can be employed in the recipe, the global reaction route mapping (GRRM) method was employed in this study. By combining GRRM with the proposed recipe, all critical regions, that is, transition states, conical intersections, intersection seams, and local minima, associated with multiple PESs, can be explored automatically. As illustrative examples, applications to photochemistry of formaldehyde and acetone are described. In these examples as well as in recent applications to other systems, the present approach led to discovery of many unexpected nonadiabatic pathways, by which some complicated experimental data have been explained very clearly.
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24
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Daniel Freeman C, Grubb MP, Lane IC, North SW. Vibrational state-selected photodissociation of ClO+. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.09.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Mar KA, Van Wyngarden AL, Liang CW, Lee YT, Lin JJ, Boering KA. A crossed beam study of 18O( 3P)+NO 2 and 18O( 1D)+NO 2: Isotope exchange and O 2+NO formation channels. J Chem Phys 2012; 137:044302. [DOI: 10.1063/1.4736567] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Xiao H, Maeda S, Morokuma K. Global ab Initio Potential Energy Surfaces for Low-Lying Doublet States of NO3. J Chem Theory Comput 2012; 8:2600-5. [DOI: 10.1021/ct3004035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hongyan Xiao
- Fukui Institute for Fundamental
Chemistry, Kyoto University, 34-4 Takano
Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Satoshi Maeda
- Department of Chemistry, Faculty
of Science, Hokkaido University, Sapporo,
060-0810, Japan
| | - Keiji Morokuma
- Fukui Institute for Fundamental
Chemistry, Kyoto University, 34-4 Takano
Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
- Cherry L.
Emerson Center for Scientific
Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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27
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Maeda S, Taketsugu T, Morokuma K. Automated Exploration of Photolytic Channels of HCOOH: Conformational Memory via Excited-State Roaming. J Phys Chem Lett 2012; 3:1900-1907. [PMID: 26292011 DOI: 10.1021/jz300728q] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To elucidate the photodissociation mechanism of HCOOH, we systematically explored reaction pathways starting from the first excited singlet state (S1) by using automated reaction path search methods. All critical points, that is, minima, transition states, minimum energy conical intersections, and minima on seam of crossing, for the S0, T1, and S1 potential energy surfaces (PESs) obtained in the present search were optimized at the CASPT2 level. The structure list obtained by the search explained all experimentally reported photolytic channels. A new mechanism for the previously suggested but unexplained conformational memory in the 193 nm photolysis is proposed, which involves two steps: partial dissociation and succeeding roaming of one of H atoms on the S1 PES, followed by intramolecular recombination on the S0 PES after radiationless transition through a conical intersection at a partially dissociated geometry. This is partially similar to the excited-state roaming recently discovered for the NO3 radical.
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Affiliation(s)
- Satoshi Maeda
- †Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Tetsuya Taketsugu
- †Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Keiji Morokuma
- ‡Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
- §Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
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28
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Grubb MP, Warter ML, Xiao H, Maeda S, Morokuma K, North SW. No Straight Path: Roaming in Both Ground- and Excited-State Photolytic Channels of NO
3
→ NO + O
2. Science 2012; 335:1075-8. [DOI: 10.1126/science.1216911] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Michael P. Grubb
- Department of Chemistry, Texas A&M University, College Station, TX 77842, USA
| | - Michelle L. Warter
- Department of Chemistry, Texas A&M University, College Station, TX 77842, USA
| | | | | | | | - Simon W. North
- Department of Chemistry, Texas A&M University, College Station, TX 77842, USA
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29
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Affiliation(s)
| | - Scott H. Kable
- School of Chemistry, University of Sydney, Sydney, NSW, 2006 Australia
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30
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de Wit G, Heazlewood BR, Quinn MS, Maccarone AT, Nauta K, Reid SA, Jordan MJT, Kable SH. Product state and speed distributions in photochemical triple fragmentations. Faraday Discuss 2012; 157:227-41; discussion 243-84. [DOI: 10.1039/c2fd20015e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Grubb MP, Warter ML, North SW. Stereodynamics of multistate roaming. Phys Chem Chem Phys 2012; 14:6733-40. [DOI: 10.1039/c2cp40235a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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32
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Grubb MP, Warter ML, Freeman CD, West NA, Usakoski KM, Johnson KM, Bartz JA, North SW. A method for the determination of speed-dependent semi-classical vector correlations from sliced image anisotropies. J Chem Phys 2011; 135:094201. [DOI: 10.1063/1.3631343] [Citation(s) in RCA: 19] [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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33
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