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Nonintuitive Diabatic Potential Energy Surfaces for Thioanisole
Shaohong L Li1, Xuefei Xu1, Chad E Hoyer1
1Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota , Minneapolis, Minnesota 55455, United States.
The Journal of Physical Chemistry Letters
|August 13, 2015
Summary
Diabatization methods for simulating molecular dynamics were compared. Two distinct methods yielded similar potential energy surfaces, validating their use for nonadiabatic processes.
Area of Science:
- Computational Chemistry
- Theoretical Chemistry
- Quantum Chemistry
Background:
- Diabatization of potential energy surfaces is crucial for molecular dynamics simulations of nonadiabatic processes.
- The nonuniqueness and inconvenience of diabatization methods necessitate further study into optimal approaches.
- Conical intersections are key features in electronically nonadiabatic processes.
Purpose of the Study:
- To present and compare two systematic diabatization methods for the thioanisole molecule.
- To investigate the diabatization of two electronic states in a two-dimensional nuclear coordinate space.
- To validate the diabatization by comparing nonadiabatic couplings.
Main Methods:
- Diabatization using the (orbital-dependent) 4-fold way method.
- Diabatization using the (orbital-free) Boys localization method.
- Analysis of diabatic potential energy surfaces, diabatic gap, and diabatic coupling.
Main Results:
- Both methods produced strikingly similar diabatic potential energy surfaces.
- The diabatic surfaces crossed at geometries where adiabatic surfaces were well separated.
- Contours of diabatic gap and coupling were similar across both methods.
- Nonadiabatic couplings calculated from diabatic elements agreed with direct differentiation of adiabatic states.
Conclusions:
- The 4-fold way and Boys localization methods provide consistent diabatization for thioanisole.
- The presented diabatization is valid and suitable for molecular dynamics simulations.
- This work contributes to the ongoing study of optimal diabatization techniques.
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