###Time Dependent Density Functional Perturbation Theory (TDDFPT)

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TD-DFPT developers would be grateful if any scientific work done with TD-DFPT
contained a reference to one of the following reference papers:

turboTDDFT – A code for the simulation of molecular spectra using the Liouville–Lanczos approach to time-dependent density-functional perturbation theory  Original Research Article
Author(s): Osman Baris Malcioglu, Ralph Gebauer, Dario Rocca, Stefano Baroni
Computer Physics Communications, In Press, Accepted Manuscript, Available online 29 April 2011

Turbo charging time-dependent density-functional theory with Lanczos chains
Author(s): Rocca D, Gebauer R, Saad Y, et al.
Source: JOURNAL OF CHEMICAL PHYSICS   Volume: 128   Issue: 15 Article Number: 154105   Published: APR 21 2008

Ultrasoft pseudopotentials in time-dependent density-functional theory
Author(s): Walker B, Gebauer R
Source: JOURNAL OF CHEMICAL PHYSICS   Volume: 127   Issue: 16 Article Number: 164106   Published: OCT 28 2007

Efficient approach to time-dependent density-functional perturbation theory for optical spectroscopy
Author(s): Walker B, Saitta AM, Gebauer R, et al.
Source: PHYSICAL REVIEW LETTERS   Volume: 96   Issue: 11 Article Number: 113001   Published: MAR 24 2006

Electron energy loss and inelastic x-ray scattering cross sections from time-dependent density-functional perturbation theory
Author(s): I. Timrov, N. Vast, R. Gebauer, and S. Baroni
Source: PHYSICAL REVIEW B   Volume: 88   Article Number: 064301   Published: AUG 2 2013

turboEELS - A code for the simulation of the electron energy loss and inelastic X-ray scattering spectra using the Liouville-Lanczos approach to time-dependent density-functional perturbation theory
Author(s): I. Timrov, N. Vast, R. Gebauer, and S. Baroni
Source: Computer Physics Communications, Volume: 196, Article Number: 460 Published: 4 JUNE 2015

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This module uses subroutines from PW and PH along with the general infrasturcture provided by
Quantum Espresso. 

The directory TDDFPT must reside immediately under the espresso directory for Makefiles to work. 

Standart compilation: Run "make tddfpt" in espresso directory where TDDFPT is a subdirectory
 
Directory Structure: 
bin      : The tddfpt related binaries
src      : The source files
Doc      : The manual
Examples : Examples and tests. If you run make under this subdirectory
           a full test is initiated (requires tddfpt to be compiled first).
           You can also perform a shorter test by "make small_test". Each example has its
           own seperate Makefile. Please refer to the README under this subdirectory for
           further information. 
tools    : Various tools:
           1) The postprocessing code for calculating absorption spectrum and polarizabilities.
           2) A script to recover reduced liouvillian in a format comprehensible to postprocessing
              code from the stdout.