DFTBaby: A software package for non-adiabatic molecular dynamics simulations based on long-range corrected tight-binding TD-DFT(B)

Abstract

A software package, called DFTBaby, is published, which provides the electronic structure needed for running non-adiabatic molecular dynamics simulations at the level of tight-binding DFT. A long-range correction is incorporated to avoid spurious charge transfer states. Excited state energies, their analytic gradients and scalar non-adiabatic couplings are computed using tight-binding TD-DFT. These quantities are fed into a molecular dynamics code, which integrates Newton’s equations of motion for the nuclei together with the electronic Schrödinger equation. Non-adiabatic effects are included by surface hopping. As an example, the program is applied to the optimization of excited states and non-adiabatic dynamics of polyfluorene. The python and Fortran source code is available at http://www.dftbaby.chemie.uni-wuerzburg.de. Program summaryProgram title: DFTBabyProgram Files doi:http://dx.doi.org/10.17632/z8hcyff9yd.1Licensing provisions: MIT licenseProgramming language: python and Fortran 90Nature of problem: Trajectory-based non-adiabatic molecular dynamics simulations in excited singlet states for closed-shell molecular systems.Solution method: The electronic structure is solved using charge-consistent tight-binding DFT with a long-range correction to avoid spurious charge transfer states. Excited state energies, their analytic gradients and scalar non-adiabatic couplings are computed using tight-binding TD-DFT. These quantities are fed in a molecular dynamics code, which integrates Newton’s equations of motion for the nuclei together with the electronic Schrödinger equation. Non-adiabatic effects are included by surface hopping.