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Imanzi K, Bostan D, McCrea M, Featherstone J, Brouard M, Babikov D. Symmetry Breaking: A Classic Example of Quantum Interference Captured by Mixed Quantum/Classical Theory. J Phys Chem Lett 2023; 14:10617-10623. [PMID: 37982682 DOI: 10.1021/acs.jpclett.3c02887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
The phenomena of propensity and inverse propensity are explored using time-dependent mixed quantum classical theory, MQCT, in which the rotational motion of the molecule is treated quantum mechanically, whereas the scattering process is described classically. Good agreement with the results of accurate full-quantum calculations is reported for a closed shell approximation to the NO + Ar system. It is shown that MQCT reproduces both phenomena in a broad range of the final states of the molecule and for various initial rotational states, offering a unique time-dependent insight. It permits seeing that both propensity and inverse propensity occur due to efficient depopulation of some states at the early postcollisional stage of the scattering process, when the molecule exists in a coherent superposition of many excited states that span a very broad range of angular momentum quantum numbers, populated by an efficient stepladder process of many consecutive transitions with small Δj.
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Affiliation(s)
- Kayla Imanzi
- Chemistry Department, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Dulat Bostan
- Chemistry Department, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
| | - Max McCrea
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Josh Featherstone
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Mark Brouard
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Dmitri Babikov
- Chemistry Department, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
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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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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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Sindhu A, Jain A. Benchmarking the Surface Hopping Method to Include Nuclear Quantum Effects. J Chem Theory Comput 2021; 17:655-665. [PMID: 33432812 DOI: 10.1021/acs.jctc.0c01065] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have benchmarked the surface hopping method to capture nuclear quantum effects in the spin-Boson model in the deep tunneling regime. The thermal populations and the rate constants calculated using the surface hopping method are compared with those calculated using Boltzmann theory and Fermi's golden rule, respectively. Additionally, we have proposed a simple kinetic model that partially includes nuclear quantum effects within Marcus theory, and the results of the surface hopping method are analyzed under the framework of this simple kinetic model. A broad range of parameters are investigated to identify the regimes for the successes and failures of the surface hopping method. This work shows that with the accurate treatment of decoherence and velocity reversal, surface hopping can generally capture the nuclear quantum effects in the deep tunneling and weak diabatic coupling regime.
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Affiliation(s)
- Aarti Sindhu
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Amber Jain
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
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5
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Origin of the "odd" behavior in the ultraviolet photochemistry of ozone. Proc Natl Acad Sci U S A 2020; 117:21065-21069. [PMID: 32817468 DOI: 10.1073/pnas.2006070117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The origin of the even-odd rotational state population alternation in the 16O2(a 1Δg) fragments resulting from the ultraviolet (UV) photodissociation of 16O3, a phenomenon first observed over 30 years ago, has been elucidated using full quantum theory. The calculated 16O2(a 1Δg) rotational state distribution following the 266-nm photolysis of 60 K ozone shows a strong even-odd propensity, in excellent agreement with the new experimental rotational state distribution measured under the same conditions. Theory indicates that the even rotational states are significantly more populated than the adjacent odd rotational states because of a preference for the formation of the A' Λ-doublet, which can only occupy even rotational states due to the exchange symmetry of the two bosonic 16O nuclei, and thus not as a result of parity-selective curve crossing as previously proposed. For nonrotating ozone, its dissociation on the excited B1A' state dictates that only A' Λ-doublets are populated, due to symmetry conservation. This selection rule is relaxed for rotating parent molecules, but a preference still persists for A' Λ-doublets. The A''/A' ratio increases with increasing ozone rotational quantum number, and thus with increasing temperature, explaining the previously observed temperature dependence of the even-odd population alternation. In light of these results, it is concluded that the previously proposed parity-selective curve-crossing mechanism cannot be a source of heavy isotopic enrichment in the atmosphere.
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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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Wallace CJ, Gunthardt CE, McBane GC, North SW. Empirical assignment of absorbing electronic state contributions to OCS photodissociation product state populations from 214 to 248 nm. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2018.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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8
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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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Zhang Y, Jónsson H, Weber PM. Coherence in nonradiative transitions: internal conversion in Rydberg-excited N-methyl and N-ethyl morpholine. Phys Chem Chem Phys 2017; 19:26403-26411. [DOI: 10.1039/c7cp05244h] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The survival of coherent wavepacket motion during internal conversions is observed in relatively large molecules, N-methyl morpholine and N-ethyl morpholine, where standard models imply fast decoherence in a statistical limit.
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Affiliation(s)
- Yao Zhang
- Department of Chemistry
- Brown University
- Providence
- USA
| | - Hannes Jónsson
- Department of Chemistry
- Brown University
- Providence
- USA
- Faculty of Physical Sciences
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Vereecken L, Glowacki DR, Pilling MJ. Theoretical Chemical Kinetics in Tropospheric Chemistry: Methodologies and Applications. Chem Rev 2015; 115:4063-114. [DOI: 10.1021/cr500488p] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Luc Vereecken
- Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - David R. Glowacki
- PULSE
Institute and Department of Chemistry, Stanford University, Stanford, California 94305, United States
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
- Department
of Computer Science, University of Bristol, Bristol BS8 1UB, United Kingdom
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Picconi D, Grebenshchikov SY. Signatures of a conical intersection in photofragment distributions and absorption spectra: photodissociation in the Hartley band of ozone. J Chem Phys 2014; 141:074311. [PMID: 25149790 DOI: 10.1063/1.4892919] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photodissociation of ozone in the near UV is studied quantum mechanically in two excited electronic states coupled at a conical intersection located outside the Franck-Condon zone. The calculations, performed using recent ab initio PESs, provide an accurate description of the photodissociation dynamics across the Hartley/Huggins absorption bands. The observed photofragment distributions are reproduced in the two electronic dissociation channels. The room temperature absorption spectrum, constructed as a Boltzmann average of many absorption spectra of rotationally excited parent ozone, agrees with experiment in terms of widths and intensities of diffuse structures. The exit channel conical intersection contributes to the coherent broadening of the absorption spectrum and directly affects the product vibrational and translational distributions. The photon energy dependences of these distributions are strikingly different for fragments created along the adiabatic and the diabatic paths through the intersection. They can be used to reverse engineer the most probable geometry of the non-adiabatic transition. The angular distributions, quantified in terms of the anisotropy parameter β, are substantially different in the two channels due to a strong anticorrelation between β and the rotational angular momentum of the fragment O2.
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Affiliation(s)
- David Picconi
- Department of Chemistry, Technische Univeristät München, Lichtenbergstr. 4, 85747 Garching, Germany
| | - Sergy Yu Grebenshchikov
- Department of Chemistry, Technische Univeristät München, Lichtenbergstr. 4, 85747 Garching, Germany
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13
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McBane GC, Schmidt JA, Johnson MS, Schinke R. Ultraviolet photodissociation of OCS: Product energy and angular distributions. J Chem Phys 2013; 138:094314. [DOI: 10.1063/1.4793275] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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McBane GC, Schinke R. Product angular distributions in the ultraviolet photodissociation of N2O. J Chem Phys 2012; 136:044314. [DOI: 10.1063/1.3679171] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Chen IC, Chen AF, Huang WT, Takahashi K, Lin JJ. Photolysis Cross-Section of Ozone Dimer. Chem Asian J 2011; 6:2925-30. [DOI: 10.1002/asia.201100526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Indexed: 11/09/2022]
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16
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Nonadiabatic dynamics with trajectory surface hopping method. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2011. [DOI: 10.1002/wcms.64] [Citation(s) in RCA: 279] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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