Nonadiabatic dynamics simulation of keto isocytosine: a comparison of dynamical performance of different electronic-structure methods

2017 ◽  
Vol 19 (29) ◽  
pp. 19168-19177 ◽  
Author(s):  
Deping Hu ◽  
Yan Fang Liu ◽  
Andrzej L. Sobolewski ◽  
Zhenggang Lan
Keyword(s):  
Electronic Structure ◽  
Dynamics Simulation ◽  
Nonadiabatic Dynamics ◽  
Electronic Structure Methods ◽  
Reaction Channels ◽  
Dynamics Simulations

Different reaction channels are obtained in the nonadiabatic dynamics simulations of isocytosine at CASSCF and ADC(2) levels.

Combining Meyer–Miller Hamiltonian with electronic structure methods for on-the-fly nonadiabatic dynamics simulations: implementation and application

2019 ◽  
Vol 21 (31) ◽  
pp. 17109-17117 ◽  
Author(s):  
Diandong Tang ◽  
Wei-Hai Fang ◽  
Lin Shen ◽  
Ganglong Cui
Keyword(s):  
Electronic Structure ◽  
Electronic Structure Calculations ◽  
Nonadiabatic Dynamics ◽  
Electronic Structure Methods ◽  
Dynamics Simulations ◽  
Structure Calculations

The MM/SQC method combined with electronic structure calculations at the level of OM2/MRCI and on-the-fly nonadiabatic dynamics simulations.

Photophysics of Auramine-O: electronic structure calculations and nonadiabatic dynamics simulations

2016 ◽  
Vol 18 (1) ◽  
pp. 403-413 ◽  
Author(s):  
Bin-Bin Xie ◽  
Shu-Hua Xia ◽  
Xue-Ping Chang ◽  
Ganglong Cui
Keyword(s):  
Electronic Structure ◽  
Electronic Structure Calculations ◽  
Nonadiabatic Dynamics ◽  
Auramine O ◽  
Dynamics Simulations ◽  
Structure Calculations

Sequential vs. concerted S1 relaxation pathways.

Electronic structure calculations and nonadiabatic dynamics simulations of excited-state relaxation of Pigment Yellow 101

2018 ◽  
Vol 20 (9) ◽  
pp. 6524-6532 ◽  
Author(s):  
Meng Che ◽  
Yuan-Jun Gao ◽  
Yan Zhang ◽  
Shu-Hua Xia ◽  
Ganglong Cui
Keyword(s):  
Electronic Structure ◽  
Excited State ◽  
Electronic Structure Calculations ◽  
Nonadiabatic Dynamics ◽  
Dynamics Simulations ◽  
Structure Calculations

Pigment Yellow 101 (PY101) is widely used as a typical pigment due to its excellent excited-state properties.

scholarly journals Nonadiabatic Dynamics Algorithms with Only Potential Energies and Gradients: Curvature-Driven Coherent Switching with Decay of Mixing and Curvature-Driven Trajectory Surface Hopping

2021 ◽  
Author(s):  
Yinan Shu ◽  
Linyao Zhang ◽  
Shaozeng Sun ◽  
Yudong Huang ◽  
Donald Truhlar ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Wave Functions ◽  
Matrix Elements ◽  
Nonadiabatic Dynamics ◽  
Time Step ◽  
Coupling Matrix ◽  
Surface Hopping ◽  
New Methods ◽  
Electronic Structure Methods ◽  
Curvature Driven

Direct dynamics by mixed quantum–classical nonadiabatic methods is an important tool for understanding processes involving multiple electronic states. Very often, the computational bottleneck of such direct simulation comes from electronic structure theory. For example, at every time step of a trajectory, nonadiabatic dynamics requires potential energy surfaces, their gradients, and the matrix elements coupling the surfaces. The need for the couplings can be alleviated by employing the time derivatives of the wave functions, which can be evaluated from overlaps of electronic wave functions at successive timesteps. However, evaluation of overlap integrals is still expensive for large systems. In addition, for electronic structure methods for which the wave functions or the coupling matrix elements are not available, nonadiabatic dynamics algorithms become inapplicable. In this work, building on recent work by Baeck and An, we propose new nonadiabatic dynamics algorithms that only require adiabatic potential energies and their gradients. The new methods are named curvature- driven coherent switching with decay of mixing (κCSDM) and curvature-driven trajectory surface hopping (κTSH). We show how powerful these new methods are in terms of computer time and good agreement with methods employing nonadiabatic coupling vectors computed in conventional ways. The lowering of the computational cost will allow longer nonadiabatic trajectories and greater ensemble averaging to be affordable, and the ability to calculate the dynamics without electronic structure coupling matrix elements extends the dynamics capability to new classes of electronic structure methods.

scholarly journals Ab initio and semi-empirical Molecular Dynamics simulations of chemical reactions in isolated molecules and in clusters

2014 ◽  
Vol 16 (21) ◽  
pp. 9760-9775 ◽  
Author(s):  
R. B. Gerber ◽  
D. Shemesh ◽  
M. E. Varner ◽  
J. Kalinowski ◽  
B. Hirshberg
Keyword(s):  
Molecular Dynamics ◽  
Electronic Structure ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Chemical Reactions ◽  
Recent Progress ◽  
Electronic Structure Methods ◽  
Dynamics Simulations ◽  
Semi Empirical ◽  
Trajectory Simulations

Recent progress in “on-the-fly” trajectory simulations of molecular reactions, using different electronic structure methods is discussed, with analysis of the insights that such calculations can provide and of the strengths and limitations of the algorithms available.

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.

scholarly journals Identification of Important Normal Modes in Nonadiabatic Dynamics Simulations by Coherence, Correlation, and Frequency Analyses

2019 ◽  
Author(s):  
Sebastian Mai ◽  
Leticia Gonzalez
Keyword(s):  
Wave Function ◽  
Degrees Of Freedom ◽  
Normal Modes ◽  
Dynamics Simulation ◽  
Nuclear Motion ◽  
Nonadiabatic Dynamics ◽  
Excitation Energies ◽  
Time Frequency ◽  
Dynamics Simulations ◽  
Low Dimensional

<div>Nonadiabatic dynamics simulations of molecular systems with a large number of nuclear degrees of freedom become increasingly feasible, but there is still a need to extract from such simulations a small number of most important modes of nuclear motion, for example to obtain general insight or to construct low-dimensional model potentials for further simulations. Standard techniques for this dimensionality reduction employ statistical methods that identify the modes that account for the largest variance in nuclear positions. However, large-amplitude motion is not necessarily a good proxy for the influence of a mode on the excited-state wave function evolution. Hence, here we report a number of analysis techniques aimed at extracting from nonadiabatic dynamics simulations the vibrational modes that are most strongly affected by the electronic excitation process and that most significantly affect the interaction of the electronic states. The first technique identifies coherent nuclear motion after excitation from the ratio between total variance and variance of the average trajectory. The second strategy employs linear regression to find normal modes that have a statistically significant effect on excitation energies, energy gaps, or wave function overlaps. The third approach uses time-frequency analysis to find normal modes where the vibrational frequencies change in the course of the dynamics simulation. All three techniques are applied to the case of surface hopping trajectories of [Re(CO)<sub>3</sub>(Im)(Phen)]<sup>+</sup> (Im=imidazole; Phen=1,10-phenanthroline), showing that in this transition metal complex the nonadiabatic dynamics is dominated by a small number of carbonyl and phenanthroline in-plane stretch modes.</div><div><br></div>

Chiral conversion and periodical decay in bridged-azobenzene photoisomerization: an ab initio on-the-fly nonadiabatic dynamics simulation

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 39542-39552 ◽  
Author(s):  
Wanqing Gao ◽  
Le Yu ◽  
Xiaolei Zheng ◽  
Yibo Lei ◽  
Chaoyuan Zhu ◽  
...  
Keyword(s):  
Ab Initio ◽  
Dynamics Simulation ◽  
Nonadiabatic Dynamics ◽  
Surface Hopping ◽  
Dynamics Simulations

On-the-fly trajectory surface hopping dynamics simulations on the cis ↔ trans photoisomerization mechanisms of bridged-azobenzene upon S1 excitation at the CASSCF level.

scholarly journals Flexible and Responsive Nature of 2D Layered Conductive Metal-Organic Frameworks Determine Their Catalytic Activity in Oxidative Dehydrogenation of Propane

2020 ◽  
Author(s):  
Mohammad R. Momeni ◽  
Zeyu Zhang ◽  
Farnaz A. Shakib
Keyword(s):  
Electronic Structure ◽  
Catalytic Activity ◽  
Active Sites ◽  
Metal Organic Framework ◽  
Electronic Structure Calculations ◽  
Electronic Structure Methods ◽  
Catalytically Active ◽  
Metal Organic ◽  
Dynamics Simulations ◽  
Structure Calculations

A multi-faceted approach is introduced for investigating the effects of intrinsic and guest(water)-induced structural transformations/deformations and heterogeneity on catalytic activity of the 2D π-stacked layered Co3(HTTP)2, HTTP = hexathiotriphenylene, metal-organic framework. Through comprehensive molecular dynamics simulations coupled with periodic and cluster electronic structure calculations, we uncover a complex array of catalytically active sites in 2D Co3(HTTP)2 MOF which would have been entirely missed if conventional static electronic structure methods were to be employed.

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