The photoinduced isomerization mechanism of the 2-(1-(methylimino)methyl)-6-chlorophenol (SMAC): Nonadiabatic surface hopping dynamics simulations

2018 ◽  
Vol 149 (3) ◽  
pp. 034309 ◽  
Author(s):  
Li Zhao ◽  
Jianyong Liu ◽  
Panwang Zhou
Keyword(s):  
Surface Hopping ◽  
Isomerization Mechanism ◽  
Dynamics Simulations ◽  
Photoinduced Isomerization

scholarly journals Insights into the deactivation of 5-bromouracil after ultraviolet excitation

2017 ◽  
Vol 375 (2092) ◽  
pp. 20160202 ◽  
Author(s):  
Francesca Peccati ◽  
Sebastian Mai ◽  
Leticia González
Keyword(s):  
Gas Phase ◽  
Ground State ◽  
Surface Hopping ◽  
Ultraviolet Excitation ◽  
Quantum Chemistry Calculations ◽  
Electronic Structure Methods ◽  
Dna Strands ◽  
Potential Applications ◽  
Adiabatic Dynamics ◽  
Dynamics Simulations

5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-bromouracil after ultraviolet irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and non-adiabatic dynamics simulations. It is found that, after irradiation to the bright ππ * state, three main relaxation pathways are, in principle, possible: relaxation back to the ground state, intersystem crossing (ISC) and C–Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground-state relaxation should be the predominant deactivation pathway in the gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS (multi-reference configuration interaction including single excitations) was used in surface hopping simulations to compute the ultrafast ISC dynamics, which mostly involves the 1 n O π * and 3 ππ * states. This article is part of the themed issue ‘Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces’.

Photochemical mechanism of 1,5-benzodiazepin-2-one: electronic structure calculations and nonadiabatic surface-hopping dynamics simulations

2019 ◽  
Vol 21 (19) ◽  
pp. 10086-10094 ◽  
Author(s):  
Shu-Hua Xia ◽  
Meng Che ◽  
Yan Liu ◽  
Yan Zhang ◽  
Ganglong Cui
Keyword(s):  
Electronic Structure ◽  
Electronic Structure Calculations ◽  
Surface Hopping ◽  
Dynamics Simulations ◽  
Structure Calculations

The photochemical mechanism of 1,5-benzodiazepin-2-one is studied by combined static electronic structure calculations and nonadiabatic surface-hopping dynamics simulations.

scholarly journals Nonadiabatic Dynamics in Multidimensional Complex Potential Energy Surfaces

2020 ◽  
Author(s):  
Fábris Kossoski ◽  
Mario Barbatti
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Electron Attachment ◽  
Complex Surface ◽  
Nonadiabatic Dynamics ◽  
Surface Hopping ◽  
Molecular Systems ◽  
Out Of Plane ◽  
Dynamics Simulations ◽  
Energy Surfaces

<p>Despite the continuous development of theoretical methodologies for describing nonadiabatic dynamics of molecular systems, there is a lack of approaches for processes where the norm of the wave function is not conserved, i.e., when an imaginary potential accounts for some irreversible decaying mechanism. Current approaches rely on building potential energy surfaces of reduced dimensionality, which is not optimal for more involving and realistic multidimensional problems. Here, we present a novel methodology for describing the dynamics of complex-valued molecular Hamiltonians, which is a generalisation of the trajectory surface hopping method. As a first application, the complex surface fewest switches surface hopping (CS-FSSH) method was employed to survey the relaxation mechanisms of the shape resonant anions of iodoethene. We have provided the first detailed and dynamical picture of the p*/s* mechanism of dissociative electron attachment in halogenated unsaturated compounds, which is believed to underlie electron-induced reactions of several molecules of interest. Electron capture into the p* orbital promotes C=C stretching and out-of-plane vibrations, followed by charge transfer from the double bond into the s* orbital at the C-I bond, and, finally, release of the iodine ion, all within only 15 fs. On-the-fly dynamics simulations of a vast class of processes can be envisioned with the CS-FSSH methodology, including autoionisation from transient anions, core-ionised and superexcited states, Auger and interatomic Coulombic decay, and time-dependent luminescence.</p>

scholarly journals Highly efficient surface hopping dynamics using a linear vibronic coupling model

2019 ◽  
Vol 21 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Felix Plasser ◽  
Sandra Gómez ◽  
Maximilian F. S. J. Menger ◽  
Sebastian Mai ◽  
Leticia González
Keyword(s):  
Internal Conversion ◽  
Coupling Model ◽  
Vibronic Coupling ◽  
Intersystem Crossing ◽  
Nonadiabatic Dynamics ◽  
Surface Hopping ◽  
Highly Efficient ◽  
Dynamics Simulations

A highly efficient protocol for performing nonadiabatic dynamics simulations is implemented and applied to ultrafast internal conversion and intersystem crossing in various molecules.

scholarly journals Nonadiabatic dynamics simulations of singlet fission in 2,5-bis(fluorene-9-ylidene)-2,5-dihydrothiophene crystals

2019 ◽  
Vol 21 (2) ◽  
pp. 692-701 ◽  
Author(s):  
Meilani Wibowo ◽  
Maurizio Persico ◽  
Giovanni Granucci
Keyword(s):  
Quantum Yield ◽  
Nonadiabatic Dynamics ◽  
Singlet Fission ◽  
Surface Hopping ◽  
Dynamics Simulations

Singlet fission mechanism and quantum yield for a thienoquinodal compound from surface hopping simulations.

scholarly journals Excited-state intramolecular proton transfer to carbon atoms: nonadiabatic surface-hopping dynamics simulations

2015 ◽  
Vol 17 (15) ◽  
pp. 9687-9697 ◽  
Author(s):  
Shu-Hua Xia ◽  
Bin-Bin Xie ◽  
Qiu Fang ◽  
Ganglong Cui ◽  
Walter Thiel
Keyword(s):  
Electronic Structure ◽  
Excited State ◽  
Proton Transfer ◽  
Intramolecular Proton Transfer ◽  
Nonadiabatic Dynamics ◽  
Surface Hopping ◽  
Dynamics Simulations

The combined electronic structure computations and nonadiabatic dynamics simulations show that excited-state intramolecular proton transfer to carbon atoms can be ultrafast.

Timescales of N–H bond dissociation in pyrrole: a nonadiabatic dynamics study

2015 ◽  
Vol 17 (29) ◽  
pp. 19012-19020 ◽  
Author(s):  
Marin Sapunar ◽  
Aurora Ponzi ◽  
Sermsiri Chaiwongwattana ◽  
Momir Mališ ◽  
Antonio Prlj ◽  
...  
Keyword(s):  
Excitation Wavelength ◽  
Nonadiabatic Dynamics ◽  
Surface Hopping ◽  
Bond Dissociation ◽  
Dynamics Simulations

The excitation wavelength dependent photodynamics of pyrrole are investigated by surface-hopping nonadiabatic dynamics simulations. The results are explained in terms of correct Rydberg–valence interaction in the lowest B2 state.

Reduced-dimensional surface hopping with offline–online computations

2021 ◽  
Author(s):  
Zachary Morrow ◽  
Hyuk-Yong Kwon ◽  
Carl Tim Kelley ◽  
Elena Jakubikova
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Molecular Dynamics Simulations ◽  
Potential Energy Surfaces ◽  
Energy Levels ◽  
Surface Hopping ◽  
Dynamics Simulations ◽  
Energy Surfaces ◽  
Nuclear Geometry ◽  
Dimensional Surface

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...

scholarly journals Nonadiabatic Dynamics in Multidimensional Complex Potential Energy Surfaces

2020 ◽  
Author(s):  
Fábris Kossoski ◽  
Mario Barbatti
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Electron Attachment ◽  
Complex Surface ◽  
Nonadiabatic Dynamics ◽  
Surface Hopping ◽  
Molecular Systems ◽  
Out Of Plane ◽  
Dynamics Simulations ◽  
Energy Surfaces

<p>Despite the continuous development of theoretical methodologies for describing nonadiabatic dynamics of molecular systems, there is a lack of approaches for processes where the norm of the wave function is not conserved, i.e., when an imaginary potential accounts for some irreversible decaying mechanism. Current approaches rely on building potential energy surfaces of reduced dimensionality, which is not optimal for more involving and realistic multidimensional problems. Here, we present a novel methodology for describing the dynamics of complex-valued molecular Hamiltonians, which is a generalisation of the trajectory surface hopping method. As a first application, the complex surface fewest switches surface hopping (CS-FSSH) method was employed to survey the relaxation mechanisms of the shape resonant anions of iodoethene. We have provided the first detailed and dynamical picture of the π*/σ* mechanism of dissociative electron attachment in halogenated unsaturated compounds, which is believed to underlie electron-induced reactions of several molecules of interest. Electron capture into the π* orbital promotes C=C stretching and out-of-plane vibrations, followed by charge transfer from the double bond into the σ* orbital at the C-I bond, and, finally, release of the iodine ion, all within only 15 fs. On-the-fly dynamics simulations of a vast class of processes can be envisioned with the CS-FSSH methodology, including autoionisation from transient anions, core-ionised and superexcited states, Auger and interatomic Coulombic decay, and time-dependent luminescence.</p>

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