Tight-binding parameters for charge transfer along DNA

TL;DR

This paper systematically derives tight-binding parameters for charge transfer in DNA, providing a detailed set of microscopic quantities crucial for modeling electron and hole transport along the DNA double helix.

Contribution

It introduces a comprehensive calculation of charge transfer parameters in DNA bases and base pairs using the linear combination of atomic orbitals method, aligning well with experimental data.

Findings

HOMO and LUMO energies match experimental values

Hole transfer hopping parameters are generally larger than electron ones

Results are consistent with existing first-principles calculations

Abstract

We systematically examine all the tight-binding parameters pertinent to charge transfer along DNA. The $\pi$ molecular structure of the four DNA bases (adenine, thymine, cytosine, and guanine) is investigated by using the linear combination of atomic orbitals method with a recently introduced parametrization. The HOMO and LUMO wavefunctions and energies of DNA bases are discussed and then used for calculating the corresponding wavefunctions of the two B-DNA base-pairs (adenine-thymine and guanine-cytosine). The obtained HOMO and LUMO energies of the bases are in good agreement with available experimental values. Our results are then used for estimating the complete set of charge transfer parameters between neighboring bases and also between successive base-pairs, considering all possible combinations between them, for both electrons and holes. The calculated microscopic quantities can be used in mesoscopic theoretical models of electron or hole transfer along the DNA double helix, as they provide the necessary parameters for a tight-binding phenomenological description based on the $\pi$ molecular overlap. We find that usually the hopping parameters for holes are higher in magnitude compared to the ones for electrons, which probably indicates that hole transport along DNA is more favorable than electron transport. Our findings are also compared with existing calculations from first principles.