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Sit MK, Das S, Samanta K. Semiclassical Dynamics on Machine-Learned Coupled Multireference Potential Energy Surfaces: Application to the Photodissociation of the Simplest Criegee Intermediate. J Phys Chem A 2023; 127:2376-2387. [PMID: 36856588 DOI: 10.1021/acs.jpca.2c07229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Determination of high-dimensional potential energy surfaces (PESs) and nonadiabatic couplings have always been quite challenging. To this end, machine learning (ML) models, trained with a finite set of ab initio data, allow accurate prediction of such properties. To express the PESs in terms of atomic contributions is the cornerstone of any ML based technique because it can be easily scaled to large systems. In this work, we have constructed high fidelity PESs and nonadiabatic coupling terms at the CASSCF level of ab initio data using a machine learning technique, namely, kernel-ridge regression. Additional MRCI-level calculations were carried out to assess the quality of the PESs. We use these machine-learned PESs and nonadiabatic couplings to simulate excited-state molecular dynamics based on Tully's fewest-switches surface hopping method (FSSH). FSSH is a semiclassical method in which nuclei move on the PESs due to the electrons according to the laws of classical mechanics. Nonadiabatic effects are taken into account in terms of transitions between PESs. We apply this scheme to study the O-O photodissociation of the simplest Criegee intermediate (CH2OO). The FSSH trajectories were initiated on the lowest optically bright singlet excited state (S2) and propagated along the three most important internal coordinates, namely, O-O and C-O bond distances and the COO bond angle. Some of the trajectories end up on energetically lower PESs as a result of radiationless transfer through conical intersections. All of the trajectories lead to the dissociation of the O-O bond due to the dissociative nature of the excited PESs through one of the two dissociative channels. The simulation reveals that there is about 88.4% probability of dissociation through the lower channel leading to the H2CO (X1A1) and O (1D) products, whereas there is only 11.6% probability of dissociation through the upper channel leading to H2CO (a3A″) and O (3P) products.
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Affiliation(s)
- Mahesh K Sit
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Argul, Odisha 752050, India
| | - Subhasish Das
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Argul, Odisha 752050, India
| | - Kousik Samanta
- School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Argul, Odisha 752050, India
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Lipson JE, Trabelsi T, Francisco JS. Spectroscopy and photochemistry of ClSSO. J Chem Phys 2023; 158:024302. [PMID: 36641416 DOI: 10.1063/5.0131665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Sulfur-chlorine cycles play a role in the atmosphere of Venus. It is thought that many sulfur-chlorine bearing molecules could be present in Venus's atmosphere and play an important role in its chemical processes. The goal of this work is to provide new insight into the electronic structure and spectroscopy of the [Cl, S, S, O] molecular system. Eight isomers could be formed, but only three were found to be thermodynamically stable relative to the first dissociation limit. We spectroscopically characterized the two lowest energy stable isomers, C1-ClSSO and trans-ClSSO, using the accurate CCSD(T)-F12/aug-cc-pVTZ method. The dipole moments of the two lowest energy stable isomers are predicted to be 1.90 and 1.60 debye, respectively. The C1-ClSSO isomer is suitable for laser induced fluorescence detection since the lowest excited electronic states absorb in the visible, ∼610 nm, and near UV region, 330 nm. We mapped the evolution of the low-lying excited electronic states along the ClS, SS, and SO bond lengths to find that the production of ClS, SO, or S2O is plausible, whereas the production of ClS2 is not allowed.
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Affiliation(s)
- Juliette E Lipson
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
| | - Tarek Trabelsi
- Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
| | - Joseph S Francisco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
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Li Y, Gong Q, Yang J, Feng Q, Song T, Wang W, Liu F. Hydrogen bond, ring tension and π-conjugation effects: methyl and vinyl substitutions dramatically change the photodynamics of Criegee intermediates. Phys Chem Chem Phys 2020; 22:15295-15302. [PMID: 32618986 DOI: 10.1039/d0cp01873b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The substitution effect in chemistry is a concept that is probably too common to mention, while for a molecule with an elusive electronic structure, substitution can introduce an unusual effect that dramatically tunes the chemical process. To reveal the substitution effects on the photodynamics of Criegee Intermediates (CIs), we carried out the multireference CASSCF trajectory surface-hopping (TSH) molecular dynamics and CASPT2 electronic-structure calculations for a methyl-substituted CI (MCI) and a vinyl-substituted CI (VCI). The results show that for different substituents, the hydrogen bond, ring tension and π-conjugation not only alter the relative stabilities of the conformers/configurations, but also dramatically change the photo-induced channel of CIs. For an anti-MCI, the dominant channel starting from the S1 state is the ring-closure process leading to dioxirane, while in the syn configuration, the intramolecular CHO hydrogen bond hinders the rotation around the C-O bond and thus leads to a high yield of in-plane O-O dissociation towards acetaldehyde (X1A') and the O(1D) atom. In a VCI with an unsaturated substituent, the π-conjugation greatly strengthens the O-O bond and therefore no O-O dissociation is observed in all configurations. In addition, the CHO hydrogen bond in the syn(CO)-VCI further stabilizes the S1-state intermediates and makes them less reactive; in contrast, isomerization to dioxirane becomes the globally dominant channel in the anti(CO)-VCI. The dramatic substitution effects by saturated and unsaturated substituents on CIs found here will deepen the understanding of Criegee-intermediate chemistry.
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Affiliation(s)
- Yazhen Li
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, P. R. China.
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Trabelsi T, Rohacs N, Francisco JS. Photochemistry from low-lying states of HOSO . J Chem Phys 2020; 152:134302. [PMID: 32268736 DOI: 10.1063/5.0001867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using configuration interaction ab initio methods, the evolution of the lowest electronic states of singlet and triplet spin multiplicities of HOSO+ along the stretching and bending coordinates of is investigated. Equilibrium geometries, rotational constants, and harmonic vibrational frequencies of the lowest electronic states are calculated, i.e., X1A', 11A″, 13A', and 13A″. The global minimum of the 11A″ state is located below the first dissociation limit and its calculated lifetime is predicted to be 0.40 µs, making it suitable for detection by laser-induced fluorescence. According to the potential energy surfaces, HOSO+ should produce SO2 + and H after ultraviolet photon absorption to the 21A' state. This work opens the door to investigate the branching ratio and the production rates of SO2 +, SO+, and OH from HOSO+. These insights can help understand the SO2 cycle in the earth's atmosphere and its effect on cooling our planet.
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Affiliation(s)
- Tarek Trabelsi
- Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
| | - Natasa Rohacs
- Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
| | - Joseph S Francisco
- Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
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Wagner JP. Gauging stability and reactivity of carbonyl O-oxide Criegee intermediates. Phys Chem Chem Phys 2019; 21:21530-21540. [PMID: 31536065 DOI: 10.1039/c9cp03790j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we evaluated the effect of substitution on the stability and reactivity of carbonyl O-oxide Criegee intermediates (CIs). In this regard, we computed a set of more than 50 carbonyl oxides at the CBS-QB3 level of theory and assessed their stability by means of an isodesmic reaction equation defining a carbonyl oxide stabilization energy (COSE). Almost all substituents are stabilizing and amino groups in particular leading to COSE values of almost 60 kcal mol-1. As opposed to π-donors, substituents with a strong σ-electron pull destabilize the C[double bond, length as m-dash]O-O group. Furthermore, we studied how the intrinsic stabilization of the Criegee intermediate is reflected in its C[double bond, length as m-dash]O and O-O bond lengths as well as the partial charges on the individual atoms of the carbonyl oxide moiety. As a potential measure for reactivity, we determined the adiabatic singlet-triplet energy gap of all carbonyl oxides. Amino substituted CIs exhibit high-lying triplet states and have relatively large barriers towards addition of water or the OH radical. However, the ΔES-T cannot serve as a rigorous measure for carbonyl oxide reactivity.
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Affiliation(s)
- J Philipp Wagner
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
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Trabelsi T, Anglada JM, Ruiz-López MF, Francisco JS. Photochemistry of HOSO radical in the gas phase. J Chem Phys 2019; 151:111103. [DOI: 10.1063/1.5119704] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Tarek Trabelsi
- Department of Earth and Environment Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
| | - Josep M. Anglada
- Departament de Química Biològica (IQAC – CSIC), c/Jordi Girona 18, E-08034 Barcelona, Spain
| | - Manuel F. Ruiz-López
- Laboratoire de Physique et Chimie Théoriques, UMR CNRS 7019, University of Lorraine, CNRS, BP 70239, 54506 Vandoeuvre-lès-Nancy, France
| | - Joseph S. Francisco
- Department of Earth and Environment Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
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Watson NAI, Black JA, Stonelake TM, Knowles PJ, Beames JM. An Extended Computational Study of Criegee Intermediate-Alcohol Reactions. J Phys Chem A 2018; 123:218-229. [PMID: 30507197 DOI: 10.1021/acs.jpca.8b09349] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
High-level ab initio calculations (DF-LCCSD(T)-F12a//B3LYP/aug-cc-pVTZ) are performed on a range of stabilized Criegee intermediate (sCI)-alcohol reactions, computing reaction coordinate energies, leading to the formation of α-alkoxyalkyl hydroperoxides (AAAHs). These potential energy surfaces are used to model bimolecular reaction kinetics over a range of temperatures. The calculations performed in this work reproduce the complicated temperature-dependent reaction rates of CH2OO and (CH3)2COO with methanol, which have previously been experimentally determined. This methodology is then extended to compute reaction rates of 22 different Criegee intermediates with methanol, including several intermediates derived from isoprene ozonolysis. In some cases, sCI-alcohol reaction rates approach those of sCI-(H2O)2. This suggests that in regions with elevated alcohol concentrations, such as urban Brazil, these reactions may generate significant quantities of AAAHs and may begin to compete with sCI reactions with other trace tropospheric pollutants such as SO2. This work also demonstrates the ability of alcohols to catalyze the 1,4-H transfer unimolecular decomposition of α-methyl substituted sCIs.
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Affiliation(s)
- Nathan A I Watson
- School of Chemistry , Cardiff University , Main Building, Park Pl , Cardiff CF10 3AT , United Kingdom
| | - Joshua A Black
- School of Chemistry , Cardiff University , Main Building, Park Pl , Cardiff CF10 3AT , United Kingdom
| | - Thomas M Stonelake
- School of Chemistry , Cardiff University , Main Building, Park Pl , Cardiff CF10 3AT , United Kingdom
| | - Peter J Knowles
- School of Chemistry , Cardiff University , Main Building, Park Pl , Cardiff CF10 3AT , United Kingdom
| | - Joseph M Beames
- School of Chemistry , Cardiff University , Main Building, Park Pl , Cardiff CF10 3AT , United Kingdom
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Li Y, Gong Q, Yue L, Wang W, Liu F. Photochemistry of the Simplest Criegee Intermediate, CH 2OO: Photoisomerization Channel toward Dioxirane Revealed by CASPT2 Calculations and Trajectory Surface-Hopping Dynamics. J Phys Chem Lett 2018; 9:978-981. [PMID: 29420035 DOI: 10.1021/acs.jpclett.8b00023] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The photochemistry of Criegee intermediates plays a significant role in atmospheric chemistry, but it is relatively less explored compared with their thermal reactions. Using multireference CASPT2 electronic structure calculations and CASSCF trajectory surface-hopping molecular dynamics, we have revealed a dark-state-involved A1A → X1A photoisomerization channel of the simple Criegee intermediate (CH2OO) that leads to a cyclic dioxirane. The excited molecules on the A1A state, which can have either originated from the B1A state via B1A → A1A internal conversion or formed by state-selective electronic excitation, is driven by the out-of-plane motion toward a perpendicular A/X1A minimal-energy crossing point (MECI) then radiationless decay to the ground state with an average time constant of ∼138 fs, finally forming dioxirane at ∼254 fs. The dynamics starting from the A1A state show that the quantum yield of photoisomerization from the simple Criegee intermediate to dioxirane is 38%. The finding of the A1A → X1A photoisomerization channel is expected to broaden the reactivity profile and deepen the understanding of the photochemistry of Criegee intermediates.
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Affiliation(s)
- Yazhen Li
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China
| | - Qianqian Gong
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China
| | - Ling Yue
- School of Sciences, Xi'an Jiaotong University , Xi'an, Shaanxi 710049, People's Republic of China
| | - Wenliang Wang
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China
| | - Fengyi Liu
- Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an, Shaanxi 710062, People's Republic of China
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