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[Licence| Download | New Version Template] aeix_v2_0.tar.gz(119321 Kbytes)
Manuscript Title: turboTDDFT 2.0 - Hybrid functionals and new algorithms within time-dependent density-functional perturbation theory
Authors: Xiaochuan Ge, Simon J. Binnie, Dario Rocca, Ralph Gebauer, Stefano Baroni
Program title: turboTDDFT 2.0
Catalogue identifier: AEIX_v2_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 185(2014)2080
Programming language: Fortran 95, MPI.
Computer: Any computer architecture.
Operating system: GNU/Linux, AIX, IRIX, Mac OS X, and other UNIX-like OS's.
Keywords: Time-dependent density-functional theory, Quantum ESPRESSO, Optical spectra, Hybrid functionals, Lanczos recursion, Davidson diagonalization, Pseudo-Hermitian matrix.
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 supersede the previous version?: Yes

Nature 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.

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.