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Analytic non-adiabatic couplings for the spin-flip ORMAS method
1Department of Chemistry and Ames Laboratory, Iowa State University, Ames, IA 50011, USA. mark@si.msg.chem.iastate.edu.
Physical Chemistry Chemical Physics : PCCP
|December 24, 2019
Summary
Analytic non-adiabatic coupling matrix elements (NACME) were implemented for the spin-flip occupation restricted multiple active space configuration interaction (SF-ORMAS-CI) method. This advancement enables better study of non-adiabatic chemical phenomena.
Area of Science:
- Quantum chemistry
- Theoretical chemistry
- Computational chemistry
Background:
- Non-adiabatic coupling is crucial for understanding chemical dynamics.
- Accurate computational methods are needed to study these phenomena.
- Spin-flip configuration interaction (SF-CI) methods are useful for describing excited states.
Purpose of the Study:
- To derive and implement analytic non-adiabatic coupling matrix elements (NACME) for the spin-flip occupation restricted multiple active space configuration interaction (SF-ORMAS-CI) method.
- To validate the implementation of NACME within the SF-ORMAS-CI framework.
- To assess the suitability of SF-ORMAS-CI for studying non-adiabatic chemical phenomena.
Main Methods:
- Derivation and implementation of analytic NACME.
- Application of the spin-flip occupation restricted multiple active space configuration interaction (SF-ORMAS-CI) method.
- Testing on model systems: MgFH and ethylene.
Main Results:
- Successful implementation of analytic NACME for SF-ORMAS-CI.
- SF-ORMAS-CI with NACME showed good qualitative agreement with established multi-reference methods.
- The method accurately described stationary geometries and conical intersections.
Conclusions:
- The developed SF-ORMAS-CI method with NACME is suitable for investigating non-adiabatic chemical phenomena.
- This implementation provides a valuable tool for theoretical and computational chemistry research.
- Further studies can leverage this method for complex chemical systems.
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