CASPT2, CASSCF and non-adiabatic molecular dynamics (NAMD) studies on the low-lying electronic states of 1H-1,2,3-triazole photolysis

2019 ◽  
Vol 21 (46) ◽  
pp. 25809-25819
Author(s):  
Eduarda Sangiogo Gil ◽  
Bruno Bercini de Araújo ◽  
Paulo F. B. Gonçalves
Keyword(s):  
Molecular Dynamics ◽  
Electronic States ◽  
Multiconfigurational Methods

The photolysis mechanisms of 1H-1,2,3-triazole and 1H-1,2,3-benzotriazole were elucidated by employing multiconfigurational methods (CASSCF and CASPT2) and non-adiabatic molecular dynamics.

Decoherence-corrected Ehrenfest molecular dynamics on many electronic states

2020 ◽  
Vol 153 (11) ◽  
pp. 114104
Author(s):  
Michael P. Esch ◽  
Benjamin G. Levine
Keyword(s):  
Molecular Dynamics ◽  
Electronic States

scholarly journals Classical molecular dynamics simulation of electronically non-adiabatic processes

2016 ◽  
Vol 195 ◽  
pp. 9-30 ◽  
Author(s):  
William H. Miller ◽  
Stephen J. Cotton
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy Surfaces ◽  
Degrees Of Freedom ◽  
Classical Mechanics ◽  
Electronic States ◽  
Dynamics Simulation ◽  
Arbitrary Form ◽  
Electronic Density ◽  
Classical Molecular Dynamics ◽  
Adiabatic Processes

Both classical and quantum mechanics (as well as hybrids thereof, i.e., semiclassical approaches) find widespread use in simulating dynamical processes in molecular systems. For large chemical systems, however, which involve potential energy surfaces (PES) of general/arbitrary form, it is usually the case that only classical molecular dynamics (MD) approaches are feasible, and their use is thus ubiquitous nowadays, at least for chemical processes involving dynamics on a single PES (i.e., within a single Born–Oppenheimer electronic state). This paper reviews recent developments in an approach which extends standard classical MD methods to the treatment of electronically non-adiabatic processes, i.e., those that involve transitions between different electronic states. The approach treats nuclear and electronic degrees of freedom (DOF) equivalently (i.e., by classical mechanics, thereby retaining the simplicity of standard MD), and provides “quantization” of the electronic states through a symmetrical quasi-classical (SQC) windowing model. The approach is seen to be capable of treating extreme regimes of strong and weak coupling between the electronic states, as well as accurately describing coherence effects in the electronic DOF (including the de-coherence of such effects caused by coupling to the nuclear DOF). A survey of recent applications is presented to illustrate the performance of the approach. Also described is a newly developed variation on the original SQC model (found universally superior to the original) and a general extension of the SQC model to obtain the full electronic density matrix (at no additional cost/complexity).

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