Partitioned EOMEA-MBPT(2): An Efficient N(5) Scaling Method for Calculation of Electron Affinities

Area of Science:

• Quantum Chemistry
• Computational Physics
• Molecular Modeling

Background:

• The standard EOMEA-CCSD method is computationally expensive for large molecules.
• Accurate calculation of electron affinities is crucial for understanding molecular properties and reactions.

Purpose of the Study:

• To develop a computationally efficient method for calculating electron affinities of large molecules and clusters.
• To benchmark the new method against the standard EOMEA-CCSD approach.

Main Methods:

• An N(5) scaling modification to the standard EOMEA-CCSD method was developed.
• The modification utilizes matrix partitioning and perturbative approximations.
• The new method was tested on a set of 20 small molecules.

Main Results:

• The modified method exhibits lower computational scaling and storage requirements.
• Benchmarking showed an average absolute deviation of only 0.03 eV compared to the standard method.
• The method accurately predicted electron affinities for DNA and RNA nucleobases, matching experimental values.

Conclusions:

• The N(5) scaling modification provides a computationally feasible approach for large-scale electron affinity calculations.
• This method enables the study of electron affinities in complex systems like nucleobases.
• The results demonstrate excellent agreement with experimental data, validating the method's accuracy.