Electron transfer pathways from quantum dynamics simulations

FEDERICO PEDRON; FEDERICO ISSOGLIO; DARIO ESTRIN; DAMIAN A SCHERLIS

JOURNAL OF CHEMICAL PHYSICS

AMER INST PHYSICS

Año: 2020

0021-9606

This work explores the possibility of simulating an electron transfer process betweena donor and an acceptor in real time using TDDFT electron dynamics. To achievethis objective, a central issue to resolve is the definition of the initial state. Thismust be a non-equilibrium electronic state able to trigger the charge transfer dy-namics; here, two schemes are proposed to prepare such states. One is based onthe combination of the density matrices of donor and acceptor converged separatelywith the appropriate charges (for example, -1 for the donor and +1 for the accep-tor). The second approach relied on constrained DFT to localize the charge on eachfragment. With these schemes, electron transfer processes are simulated in differentmodel systems of increasing complexity: an atomic hydrogen dimer, a polyacetylenechain, and the active site of the T. cruzi hybrid type A heme peroxidase (TcAPx),for which two possible electron transfer paths have been postulated. For the lattersystem the present methodology applied in a QM-MM framework allows to establishthe relative probabilities of each path, and provides insight on the inhibition of theelectron transfer provoked by the substitution of tryptophan by phenylalanine in theW233F mutant.