DMTDHF: A full dimensional time-dependent Hartree–Fock program for diatomic molecules in strong laser fields

Abstract

We present the DMTDHF package, which investigates the non-perturbative electronic dynamics of diatomic molecules subjected to strong external laser fields by the fully propagated time-dependent Hartree–Fock theory. The package uses the prolate spheroidal coordinates, together with the finite-element method and discrete-variable representation, while short iterative Lanczos algorithm is employed for the time propagation. This package can be applied to diatomic molecules with many electrons, and is implemented to allow easy extensions for additional capabilities. Program summaryProgram title: DMTDHFCatalogue identifier: AEWN_v1_0Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEWN_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 702996No. of bytes in distributed program, including test data, etc.: 7336872Distribution format: tar.gzProgramming language: Fortran 2003.Computer: All computers with a Fortran compiler supporting at least Fortran 2003.Operating system: All operating systems with such a compiler. The makefile depends on a Unix-like system and needs modification under Windows.Has the code been vectorized or parallelized?: The program is able to run both in sequential and parallel mode. For parallel running, the number of processors can be arbitrary.RAM: Several GBs, depends on the size of the molecules and the number of DVR basis functions.Classification: 16.1, 16.2, 16.6.External routines: BLAS, LAPACK, FFTW3, MPINature of problem: The investigation of molecules interacting with intense laser pulses requires non-perturbative theoretical treatment. It has been evidenced that multiorbital and multipole effects come into play for strong-field physics, while the direct numerical integration of TDSE is computationally prohibitive for systems with more than two electrons. TDHF goes beyond the SAE approach and includes the response to the field of all electrons, which is helpful to resolve the multielectron effects from the collective response of electrons.Solution method: The package uses the prolate spheroidal coordinates, together with the finite-elements method and discrete-variable representation, while short iterative Lanczos algorithm is employed for the time propagation.Restrictions: Currently, the spin-restricted form of TDHF is implemented, which can be applied to closed-shell molecules. However, the extension to spin-unrestricted form is straight forward.Unusual features: Due to the prolate spheroidal coordinates, the Coulomb potential is treated accurately. The calculations can converge with only a mild number of basis functions and are highly efficient due to the nature of DVR functions in calculation of the two-electron integrals.Running time: The running time depends on the size of the molecules, the number of basis functions, the duration of laser pulses, and the number of processors used. Depending on these factors, it can vary between a few hours and weeks.