Charge transfer excited state energies by perturbative delta self consistent field method

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Spectroscopy

Background:

• Accurate computation of charge transfer excitation energies is crucial for understanding molecular interactions.
• Existing methods can be computationally expensive, especially for large molecular systems.
• Tetracynoehylene (TCNE)-hydrocarbon complexes serve as model systems for studying charge transfer phenomena.

Purpose of the Study:

• To introduce and validate a novel perturbative approach for calculating charge transfer excitation energies.
• To assess the accuracy and efficiency of this new method compared to established techniques.
• To demonstrate the applicability of the method to large donor-acceptor complexes.

Main Methods:

• A recently developed perturbative approach was employed.
• Calculations were performed for specific tetracynoehylene (TCNE)-hydrocarbon complexes, including C(2)H(4)-C(2)F(4), NH(3)-F(2), pentacene-C(60), and tetraphenyl porphyrin-C(60).
• Results were benchmarked against time-dependent density functional theory (TD-DFT) using range-corrected functionals.

Main Results:

• The perturbative approach provides a reliable description of charge transfer excitation energies.
• The computed energies are comparable to those obtained via TD-DFT with optimized functionals.
• The computational cost for excited states is similar to ground-state calculations.
• Each excited state calculation is independent, facilitating scalability.

Conclusions:

• The new perturbative method is a viable and accurate tool for determining charge transfer excitation energies.
• Its computational efficiency and scalability make it suitable for large and complex donor-acceptor systems.
• This approach simplifies the study of excited states in complex molecular architectures.