Charge-transfer matrix elements by FMO-LCMO approach: Hole transfer in DNA with parameter tuned range-separated DFT

Abstract

A scheme for computing charge-transfer matrix elements with the linear combination of fragment molecular orbitals and the 'nonempirically tuned range-separated' density functional is presented. It takes account of the self-consistent orbital relaxation induced by environmental Coulomb field and the exchange interaction in fragment pairs at low computational scaling along the system size. The accuracy was confirmed numerically on benchmark systems of imidazole and furane homo-dimer cations. Applications to hole transfers in DNA nucleobase pairs and in a π-stack adenine octomer highlight the effects of orbital relaxation.

Revisiting the Charge-Transfer States at Pentacene/C60 Interfaces with the GW/Bethe–Salpeter Equation Approach

“…In a solid state, a one-electron wave function can be delocalized over multiple molecules by intermolecular electronic couplings. In FMO calculations, such the orbital delocalization effects can be treated by using the FMO-linear combination of molecular orbital (FMO-LCMO) method [38,39,48]. In the FMO-LCMO method, the one-electron Hamiltonian (Fock matrix) for an entire system is calculated on the basis of fragment monomer MOs and then is diagonalized to approximate the canonical (delocalized) orbitals of the entire system.…”

FMO3-LCMO study of electron transfer coupling matrix element and pathway: Application to hole transfer between two tryptophans through cis- and trans-polyproline-linker systems

“…To include electron correlation effects, an efficient way would be with the density functional theory. For instance, we have recently found that the KohnSham orbitals from the long-range corrected functional give accurate electronic coupling energies with non-empirical tuning of the range-separation parameter [18]. The FMO3 correction will also make this scheme versatile.…”

“…In a series of papers, we have reported calculations of ET coupling matrix element and ET pathways [16][17][18] from the linear-combination of FMOs (FMO-LCMO) [19] with the two-body correction (FMO2). The method was found to give accurate ET couplings over four orders of magnitude along the ET distance when the bond detached atoms (BDA) were not involved or when the minimal atomic basis set was used [16].…”

On the long-distance charge transport in DNA-like macromolecules

“…Typical values for the intersite transfer integral are approximately 2.5 eV in conjugated polymers, while in alpha-helix its value is estimated on the order of few eV. According to different calculations, the values of the electron and hole transfer integrals in DNA are about J 1 ≈ 0.1 eV [18,26]. The values for the charge-phonon coupling parameter lie in the entire range from the weak to the strong charge-phonon coupling limit.…”