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Bhattacharya A, Singh PJ, Das S. UV-VUV absorption spectra of azido-based energetic plasticizer bis(1,3-diazido prop-2-yl)malonate in gas phase. J Chem Phys 2024; 160:014303. [PMID: 38174794 DOI: 10.1063/5.0187538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
Ultraviolet and vacuum ultraviolet photo-absorption spectra of azido (-N3)-based energetic plasticizer, bis(1,3-diazido-prop-2-yl)-malonate (abbreviated as BDAzPM), in the gas phase is recorded at room temperature and in the photon energy range of 5.5-9.9 eV using a synchrotron radiation source. Complementary computational results obtained using the time-dependent density functional theory document the vertical transition energies and oscillator strengths. Comparison of the simulated spectra with the experimental absorption spectrum of BDAzPM reveals that the early part of the absorption spectrum of BDAzPM is of pure valence excitation character, whereas the later intense part of the absorption spectrum is dominated by mixed Rydberg and valence electronic excitations.
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Affiliation(s)
- Atanu Bhattacharya
- Department of Chemistry, School of Science, Gandhi Institute of Technology and Management, GITAM, Deemed to be University, Visakhapatnam, India
| | - Param Jeet Singh
- Atomic and Molecular Physics Division, Bhabha Atomic Research Center, Mumbai, India and Homi Bhabha National Institute, Mumbai, India
| | - Suman Das
- Department of Chemistry, School of Science, Gandhi Institute of Technology and Management, GITAM, Deemed to be University, Visakhapatnam, India
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2
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Lassmann Y, Curchod BFE. Probing the sensitivity of ab initio multiple spawning to its parameters. Theor Chem Acc 2023; 142:66. [PMID: 37520272 PMCID: PMC10382418 DOI: 10.1007/s00214-023-03004-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 07/13/2023] [Indexed: 08/01/2023]
Abstract
Full multiple spawning (FMS) offers a strategy to simulate the nonadiabatic dynamics of molecular systems by describing their nuclear wavefunctions by a linear combination of coupled trajectory basis functions (TBFs). Applying a series of controlled approximations to the full multiple spawning (FMS) equations leads to the ab initio multiple spawning (AIMS), which is compatible with an on-the-fly propagation of the TBFs and an accurate description of nonadiabatic processes. The AIMS strategy and its numerical implementations, however, rely on a series of user-defined parameters. Herein, we investigate the influence of these parameters on the electronic-state population of two molecular systems- trans-azomethane and a two-dimensional model of the butatriene cation. This work highlights the stability of AIMS with respect to most of its parameters, underlines the specific parameters that require particular attention from the user of the method, and offers prescriptions for an informed selection of their value. Supplementary Information The online version contains supplementary material available at 10.1007/s00214-023-03004-w.
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Affiliation(s)
- Yorick Lassmann
- Centre for Computational Chemistry, School of Chemistry, Cantock’s Close, University of Bristol, Bristol, BS8 1TS UK
| | - Basile F. E. Curchod
- Centre for Computational Chemistry, School of Chemistry, Cantock’s Close, University of Bristol, Bristol, BS8 1TS UK
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3
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Morrow Z, Kwon HY, Kelley CT, Jakubikova E. Reduced-dimensional surface hopping with offline-online computations. Phys Chem Chem Phys 2021; 23:19547-19557. [PMID: 34524324 DOI: 10.1039/d1cp03446d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular dynamics simulations often classically evolve the nuclear geometry on adiabatic potential energy surfaces (PESs), punctuated by random hops between energy levels in regions of strong coupling, in an algorithm known as surface hopping. However, the computational expense of integrating the geometry on a full-dimensional PES and computing the required couplings can quickly become prohibitive as the number of atoms increases. In this work, we describe a method for surface hopping that uses only important reaction coordinates, performs all expensive evaluations of the true PESs and couplings only once before simulating dynamics (offline), and then queries the stored values during the surface hopping simulation (online). Our Python codes are freely available on GitHub. Using photodissociation of azomethane as a test case, this method is able to reproduce experimental results that have thus far eluded ab initio surface hopping studies.
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Affiliation(s)
- Zachary Morrow
- Department of Mathematics, North Carolina State University, Box 8205, Raleigh, NC 27695-8205, USA.
| | - Hyuk-Yong Kwon
- Department of Chemistry, North Carolina State University, Box 8204, Raleigh, NC, 27695-8204, USA.
| | - C T Kelley
- Department of Mathematics, North Carolina State University, Box 8205, Raleigh, NC 27695-8205, USA.
| | - Elena Jakubikova
- Department of Chemistry, North Carolina State University, Box 8204, Raleigh, NC, 27695-8204, USA.
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4
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Mališ M, Luber S. ΔSCF with Subsystem Density Embedding for Efficient Nonadiabatic Molecular Dynamics in Condensed-Phase Systems. J Chem Theory Comput 2021; 17:1653-1661. [DOI: 10.1021/acs.jctc.0c01200] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Momir Mališ
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Sandra Luber
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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5
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Farfan CA, Turner DB. A systematic model study quantifying how conical intersection topography modulates photochemical reactions. Phys Chem Chem Phys 2020; 22:20265-20283. [PMID: 32966428 DOI: 10.1039/d0cp03464a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Despite their important role in photochemistry and expected presence in most polyatomic molecules, conical intersections have been thoroughly characterized in a comparatively small number of systems. Conical intersections can confer molecular photoreactivity or photostability, often with remarkable efficacy, due to their unique structure: at a conical intersection, the adiabatic potential energy surfaces of two or more electronic states are degenerate, enabling ultrafast decay from an excited state without radiative emission, known as nonadiabatic transfer. Furthermore, the precise conical intersection topography determines fundamental properties of photochemical processes, including excited-state decay rate, efficacy, and molecular products that are formed. However, these relationships have yet to be defined comprehensively. In this article, we use an adaptable computational model to investigate a variety of conical intersection topographies, simulate resulting nonadiabatic dynamics, and calculate key photochemical observables. We varied the vibrational mode frequencies to modify conical intersection topography systematically in four primary classes of conical intersections and quantified the resulting rate, total yield, and product yield of nonadiabatic decay. The results reveal that higher vibrational mode frequencies reduce nonadiabatic transfer, but increase the transfer rate and resulting photoproduct formation. These trends can inform progress toward experimental control of photochemical reactions or tuning of molecules' photochemical properties based on conical intersections and their topography.
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Affiliation(s)
- Camille A Farfan
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Daniel B Turner
- Department of Chemistry, New York University, New York, NY 10003, USA
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6
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Mališ M, Luber S. Trajectory Surface Hopping Nonadiabatic Molecular Dynamics with Kohn–Sham ΔSCF for Condensed-Phase Systems. J Chem Theory Comput 2020; 16:4071-4086. [DOI: 10.1021/acs.jctc.0c00372] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Momir Mališ
- University of Zurich, Department of Chemistry, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Sandra Luber
- University of Zurich, Department of Chemistry, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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7
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Winslow M, Cross WB, Robinson D. Comparison of Spin-Flip TDDFT-Based Conical Intersection Approaches with XMS-CASPT2. J Chem Theory Comput 2020; 16:3253-3263. [PMID: 32302484 PMCID: PMC8279405 DOI: 10.1021/acs.jctc.9b00917] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
Determining conical intersection
geometries is of key importance
to understanding the photochemical reactivity of molecules. While
many small- to medium-sized molecules can be treated accurately using
multireference approaches, larger molecules require a less computationally
demanding approach. In this work, minimum energy crossing point conical
intersection geometries for a series of molecules have been studied
using spin-flip TDDFT (SF-TDDFT), within the Tamm-Dancoff Approximation,
both with and without explicit calculation of nonadiabatic coupling
terms, and compared with both XMS-CASPT2 and CASSCF calculated geometries.
The less computationally demanding algorithms, which do not require
explicit calculation of the nonadiabatic coupling terms, generally
fare well with the XMS-CASPT2 reference structures, while the relative
energetics are only reasonably replicated with the MECP structure
as
calculated with the BHHLYP functional and full nonadiabatic coupling
terms. We also demonstrate that, occasionally, CASSCF structures deviate
quantitatively from the XMS-CASPT2 structures, showing the importance
of including dynamical correlation.
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Affiliation(s)
- Max Winslow
- Department of Chemistry and Forensics, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, United Kingdom
| | - Warren B Cross
- Department of Chemistry and Forensics, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, United Kingdom
| | - David Robinson
- Department of Chemistry and Forensics, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, United Kingdom
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Minezawa N, Nakajima T. Quantum mechanical/molecular mechanical trajectory surface hopping molecular dynamics simulation by spin-flip time-dependent density functional theory. J Chem Phys 2020; 152:024119. [DOI: 10.1063/1.5132879] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Noriyuki Minezawa
- Computational Molecular Science Research Team, RIKEN Center for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Takahito Nakajima
- Computational Molecular Science Research Team, RIKEN Center for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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9
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Minezawa N, Nakajima T. Trajectory surface hopping molecular dynamics simulation by spin-flip time-dependent density functional theory. J Chem Phys 2019; 150:204120. [DOI: 10.1063/1.5096217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Noriyuki Minezawa
- Computational Molecular Science Research Team, RIKEN Center for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Takahito Nakajima
- Computational Molecular Science Research Team, RIKEN Center for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
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