On the evaluation of nonadiabatic coupling matrix elements using SA‐MCSCF/CI wave functions and analytic gradient methods. I

1984 ◽  
Vol 81 (10) ◽  
pp. 4549-4553 ◽  
Author(s):  
Byron H. Lengsfield ◽  
Paul Saxe ◽  
David R. Yarkony
Keyword(s):  
Gradient Methods ◽  
Wave Functions ◽  
Matrix Elements ◽  
Coupling Matrix ◽  
Nonadiabatic Coupling

Ab initio study of nonadiabatic coupling matrix elements between excited 22A′ and 32A′ electronic states of C2H

2001 ◽  
Vol 336 (1-2) ◽  
pp. 135-142 ◽  
Author(s):  
Alexander M. Mebel ◽  
Michael Baer ◽  
Victor M. Rozenbaum ◽  
Sheng H. Lin
Keyword(s):  
Ab Initio ◽  
Electronic States ◽  
Matrix Elements ◽  
Ab Initio Study ◽  
Coupling Matrix ◽  
Nonadiabatic Coupling

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.

First‐order nonadiabatic coupling matrix elements from multiconfigurational self‐consistent‐field response theory

1992 ◽  
Vol 97 (10) ◽  
pp. 7573-7584 ◽  
Author(s):  
Keld Lars Bak ◽  
Poul Jo/rgensen ◽  
Hans Jo/rgen Aa. Jensen ◽  
Jeppe Olsen ◽  
Trygve Helgaker
Keyword(s):  
Matrix Elements ◽  
Response Theory ◽  
Coupling Matrix ◽  
Nonadiabatic Coupling ◽  
First Order ◽  
Consistent Field ◽  
Self Consistent ◽  
Field Response ◽  
Self Consistent Field
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