Compensation States Approach in the Hybrid Diabatization Scheme: Extension to Multidimensional Data and Properties.

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Theoretical Chemistry

Background:

• Diabatization of reactive systems with multiple states is computationally challenging.
• Dissociative processes require large diabatic state bases, often leading to impractical calculations.
• Existing methods struggle with accurately representing adiabatic wave functions during drastic changes.

Purpose of the Study:

• To present an advanced diabatization technique for complex reactive systems.
• To demonstrate the evaluation of spin-orbit operators within a compact model state space.
• To extend the compensation states approach to multidimensional potential energy surface models.

Main Methods:

• Hybrid diabatization scheme utilizing wave function and energy data.
• Diabatic potential model incorporating compensation states.
• Projection of initial diabatic state space from adiabatic wave functions.
• Evaluation of spin-orbit operators using Effective Relativistic Coupling by Asymptotic Representation (ERCAR).

Main Results:

• Efficient basis representation of the electronic Hamiltonian achieved.
• Accurate evaluation of spin-orbit operators demonstrated within the model state space.
• Successful extension to multidimensional potential energy surfaces for methyl iodide.

Conclusions:

• The compensation states approach provides an efficient and accurate method for diabatizing complex reactive systems.
• The technique effectively handles dissociative processes and allows for accurate inclusion of relativistic effects.
• The extension to multidimensional potential energy surfaces broadens the applicability of the method in chemical dynamics studies.