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Direct diabatization based on nonadiabatic couplings: the N/D method.

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This study introduces a novel diabatization method using nonadiabatic couplings and energy gradients. This approach enables smoother fitting of electronic states, reducing computational time for simulations.

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Area of Science:

  • Computational chemistry
  • Quantum chemistry
  • Theoretical chemistry

Background:

  • Diabatization converts adiabatic electronic states to diabatic states for efficient simulations.
  • Existing methods face challenges with nonadiabatic couplings due to singularities and unphysical aspects.

Purpose of the Study:

  • To develop a new diabatization scheme.
  • To overcome limitations of existing methods in handling nonadiabatic couplings.

Main Methods:

  • A novel diabatization scheme is presented, utilizing components of nonadiabatic couplings and adiabatic energy gradients.
  • The method leverages the sign change of energy gradient differences across conical intersections or locally avoided crossings.

Main Results:

  • The new scheme successfully obtains diabatic states.
  • Successful application to several test systems demonstrates the method's efficacy.
  • Comparison with previous diabatization methods from the group is provided.

Conclusions:

  • Nonadiabatic couplings can be effectively used to obtain diabatic states.
  • The developed method offers a viable alternative for diabatization in computational simulations.