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Brook R, Symonds C, Shalashilin DV. Full wave function cloning for improving convergence of the multiconfigurational Ehrenfest method: Tests in the zero-temperature spin-boson model regime. J Chem Phys 2024; 161:064102. [PMID: 39120032 DOI: 10.1063/5.0221184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 07/26/2024] [Indexed: 08/10/2024] Open
Abstract
In this paper, we report a new algorithm for creating an adaptive basis set in the Multiconfigurational Ehrenfest (MCE) method, which is termed Full Cloning (FC), and test it together with the existing Multiple Cloning (MC) using the spin-boson model at zero-temperature as a benchmark. The zero-temperature spin-boson regime is a common hurdle in the development of methods that seek to model quantum dynamics. Two versions of MCE exist. We demonstrate that MC is vital for the convergence of MCE version 2 (MCEv2). The first version (MCEv1) converges much better than MCEv2, but FC improves its convergence in a few cases where it is hard to converge it with the help of a reasonably small size of the basis set.
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Affiliation(s)
- Ryan Brook
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
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2
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Makhov DV, Hutton L, Kirrander A, Shalashilin DV. Ultrafast electron diffraction of photoexcited gas-phase cyclobutanone predicted by ab initio multiple cloning simulations. J Chem Phys 2024; 160:164310. [PMID: 38661201 DOI: 10.1063/5.0203683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/02/2024] [Indexed: 04/26/2024] Open
Abstract
We present the result of our calculations of ultrafast electron diffraction (UED) for cyclobutanone excited into the S2 electronic state, which is based on the non-adiabatic dynamics simulations with the Ab Initio Multiple Cloning (AIMC) method with the electronic structure calculated at the SA(3)-CASSCF(12,12)/aug-cc-pVDZ level of theory. The key features in the UED pattern were identified, which can be used to distinguish between the reaction pathways observed in the AIMC dynamics, although there is a significant overlap between representative signals due to the structural similarity of the products. The calculated UED pattern can be compared with the experiment.
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Affiliation(s)
- Dmitry V Makhov
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
- School of Mathematics, University of Bristol, Fry Building, Woodland Road, Bristol BS8 1UG, United Kingdom
| | - Lewis Hutton
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Adam Kirrander
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
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3
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Makhov DV, Armstrong G, Chuang HH, Ambalampitiya H, Lemishko K, Mohr S, Nelson A, Tennyson J, Shalashilin D. Dissociation of Hydrofluorocarbon Molecules after Electron Impact in Plasma. J Phys Chem Lett 2024; 15:3404-3411. [PMID: 38502942 PMCID: PMC10983062 DOI: 10.1021/acs.jpclett.4c00348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/08/2024] [Accepted: 03/12/2024] [Indexed: 03/21/2024]
Abstract
The process of dissociation for two hydrofluorocarbon molecules in low triplet states excited by electron impact in plasma is investigated by ab initio molecular dynamics (AIMD). The interest in the dissociation of hydrofluorocarbons in plasma is motivated by their role in plasma etching in microelectronic technologies. Dissociation of triplet states is very fast, and the reaction products can be predicted. In this work, it was found that higher triplet states relax into the lowest triplet state within a few femtoseconds due to nonadiabatic dynamics, such that the simplest ab initio MD on the lowest triplet state seems to give a reasonable estimate of the reaction channels branching ratios. We provide evidence of the existence of simple rules for the dissociation of hydrofluorocarbon molecules in triplet states. For molecules with a double bond, the bonds adjacent to the double bond dissociate faster than the other bonds.
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Affiliation(s)
- Dmitry V. Makhov
- School
of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
- School
of Mathematics, University of Bristol, Fry Building, Woodland Road, Bristol BS8 1UG, United Kingdom
| | - Gregory Armstrong
- Quantemol
Ltd., 320 City Road,
The Angel, London EC1V
2NZ, United Kingdom
| | - Hsiao-Han Chuang
- School
of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
- School
of Mathematics, University of Bristol, Fry Building, Woodland Road, Bristol BS8 1UG, United Kingdom
| | | | - Kateryna Lemishko
- Quantemol
Ltd., 320 City Road,
The Angel, London EC1V
2NZ, United Kingdom
| | - Sebastian Mohr
- Quantemol
Ltd., 320 City Road,
The Angel, London EC1V
2NZ, United Kingdom
| | - Anna Nelson
- Quantemol
Ltd., 320 City Road,
The Angel, London EC1V
2NZ, United Kingdom
| | - Jonathan Tennyson
- Quantemol
Ltd., 320 City Road,
The Angel, London EC1V
2NZ, United Kingdom
- Department
of Physics and Astronomy, University College
London, London WC1E 6BT, United
Kingdom
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4
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Marlton SJP, McKinnon BI, Greißel P, Shiels OJ, Ucur B, Trevitt AJ. Picosecond excited-state lifetimes of protonated indazole and benzimidazole: The role of the N-N bond. J Chem Phys 2021; 155:184302. [PMID: 34773941 DOI: 10.1063/5.0071847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Certain chemical groups give rise to characteristic excited-state deactivation mechanisms. Here, we target the role of a protonated N-N chemical group in the excited-state deactivation of protonated indazole by comparison to its isomer that lacks this group, protonated benzimidazole. Gas-phase protonated indazole and protonated benzimidazole ions are investigated at room temperature using picosecond laser pump-probe photodissociation experiments in a linear ion-trap. Excited state lifetimes are measured across a range of pump energies (4.0-5.4 eV). The 1ππ* lifetimes of protonated indazole range from 390 ± 70 ps using 4.0 eV pump energy to ≤18 ps using 4.6 eV pump energy. The 1ππ* lifetimes of protonated benzimidazole are systematically longer, ranging from 3700 ± 1100 ps at 4.6 eV pump energy to 400 ± 200 ps at 5.4 eV. Based on these experimental results and accompanying quantum chemical calculations and potential energy surfaces, the shorter lifetimes of protonated indazole are attributed to πσ* state mediated elongation of the protonated N-N bond.
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Affiliation(s)
- Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Benjamin I McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Phillip Greißel
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Boris Ucur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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Makhov DV, Shalashilin DV. Simulation of the effect of vibrational pre-excitation on the dynamics of pyrrole photo-dissociation. J Chem Phys 2021; 154:104119. [DOI: 10.1063/5.0040178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Dmitry V. Makhov
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
- School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom
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Booth RS, Annesley CJ. Photoinduced Intermolecular Electron Transfer in Gas Phase Ion Pairs of the 1-Ethyl-3-methylimidazolium Cation and the Bis(trifluoromethylsulfonyl)imide Anion. J Phys Chem A 2020; 124:9683-9691. [PMID: 33185452 DOI: 10.1021/acs.jpca.0c06018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, the UV photodissociation of gas phase ion pairs of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim]+[tf2n]-, is shown to proceed primarily through radical intermediates. [emim]+[tf2n]- ion pairs have been shown previously to undergo two-photon-dependent dissociation, but the mechanisms of this have not been probed in detail. By employing a two-laser pump probe spectroscopy and time-dependent density functional theory (TD-DFT) calculations, we have illustrated that one of the major UV photodissociation pathways in [emim]+[tf2n]- ion pairs is an intermolecular electron transfer wherein the anion transfers an electron to the cation resulting in two neutral open-shelled products. These products were observable for at least 1.6 μs post photodissociation, the experimental limit, via detection of the [emim]+ cation. This data demonstrates that the likely photoproducts of [emim]+[tf2n]- UV photodissociation are two neutral species that separate spatially, demonstrated through lack of observed relaxation pathways such as electron recombination. TD-DFT and frontier molecular orbital analysis calculations at the MN15/6-311++G(d,p) level are employed to aid in identifying excited state characteristics and support the interpretations of the experimental data. The energetic onset of the intermolecular electron transfer is consistent with previously observed [emim]+[tf2n]- absorption spectra in the bulk and gas phases. The similarities between bulk and gas phase UV spectra imply that this electron-transfer pathway may be a major photodissociation channel in both phases.
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Affiliation(s)
- Ryan S Booth
- Institute for Scientific Research, Boston College, Chestnut Hill, Boston, Massachusetts 02467, United States
| | - Christopher J Annesley
- Space Vehicles Directorate, Air Force Research Laboratory, Kirtland AFB, Albuquerque, New Mexico 87117, United States
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Bramley O, Symonds C, Shalashilin DV. Quantum system-bath dynamics with quantum superposition sampling and coupled generalized coherent states. J Chem Phys 2019. [DOI: 10.1063/1.5100145] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Oliver Bramley
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Christopher Symonds
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
- School of Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
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