TurboTDDFT 2.0—Hybrid functionals and new algorithms within time-dependent density-functional perturbation theory

Abstract

We present a new release of the turboTDDFT code featuring an implementation of hybrid functionals, a recently introduced pseudo-Hermitian variant of the Liouville–Lanczos approach to time-dependent density-functional perturbation theory, and a newly developed Davidson-like algorithm to compute selected interior eigenvalues/vectors of the Liouvillian super-operator. Our implementation is thoroughly validated against benchmark calculations performed on the cyanin (C21O11H21) molecule using the Gaussian 09 and turboTDDFT 1.0 codes. Program summaryProgram title: turboTDDFT 2.0Catalogue identifier: AEIX_v2_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIX_v2_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: GNU General Public License, version 2No. of lines in distributed program, including test data, etc.: 5995995No. of bytes in distributed program, including test data, etc.: 122184812Distribution format: tar.gzProgramming language: Fortran 95, MPI.Computer: Any computer architecture.Operating system: GNU/Linux, AIX, IRIX, Mac OS X, and other UNIX-like OS’s.Classification: 16.2, 16.6, 7.7.External routines:turboTDDFT 2.0 is a tightly integrated component of the Quantum ESPRESSO distribution and requires the standard libraries linked by it: BLAS, LAPACK, FFTW, MPI.Does the new version supercede the previous version?: YesNature of problem:Calculation of the optical absorption spectra of molecular systems.Solution method:Electronic excited states are addressed by linearized time-dependent density-functional theory within the plane-wave pseudo-potential method. The dynamical polarizability can be computed in terms of the resolvent of the Liouvillian super-operator, using a pseudo-Hermitian variant of the Lanczos recursion scheme. As an alternative, individual eigenvalues of the Liouvillian can be computed via a newly introduced variant of the Davidson method. In both cases, hybrid functionals can now be used.Reasons for new version:To implement new features.Summary of revisions:New features implemented: 1.Hybrid functionals.2.Pseudo-Hermitian Lanczos recursion algorithm.3.All-new Davidson-like solver for the Liouvillian eigenvalue equation (“Casida equation”).Restrictions:Spin-restricted formalism. Linear-response regime. Adiabatic XC kernels only. Hybrid functionals are only accessible using norm-conserving pseudo-potentials.Unusual features:No virtual orbitals are used, nor even calculated. Within the Lanczos method a single recursion gives access to the whole optical spectrum; when computing individual excitations using the Davidson method, interior eigenvalues can be easily targeted.Additional comments:!!!!! The distribution file for this program is over 121 Mbytes and therefore is not delivered directly when download or E-mail is requested. Instead a html file giving details of how the program can be obtained is sent.Running time:From a few minutes for small molecules on serial machines up to many hours on multiple processors for complex nanosystems with hundreds of atoms.