Introduction

This guide covers the installation and usage of Quantum-ESPRESSO (opEn-Source Package for Research in Electronic Structure, Simulation, and Optimization), version 3.0.

The Quantum-ESPRESSO package contains the following codes for the calculation of electronic-structure properties within Density-Functional Theory, using a Plane-Wave basis set and pseudopotentials:

• PWscf (Plane-Wave Self-Consistent Field).
• CP (Car-Parrinello).

and the following auxiliary codes:

• PWgui (Graphical User Interface for PWscf): a graphical interface for producing input data files for PWscf.
• atomic: a program for atomic calculations and generation of pseudopotentials.
• iotk: an Input-Output ToolKit.

The Quantum-ESPRESSO codes work on many different types of Unix machines, including parallel machines using Message Passing Interface (MPI). Running Quantum-ESPRESSO on Mac OS X and MS-Windows is also possible: see section , ``Installation''.

Further documentation, beyond what is provided in this guide, can be found in:

• the Doc/ directory of the Quantum-ESPRESSO distribution

  In particular the INPUT_* files contain the detailed listing of available input variables and cards.

• the various README files found in the distribution
• the Pw_forum mailing list (pw_forum@pwscf.org)

  You can subscribe to this list and browse and search its archives from the PWscf web site (http://www.pwscf.org/). Only subscribed users can post. Please search the archives before posting: your question may have already been answered.

• the ``Scientific Software'' page of the Democritos web site
  (http://www.democritos.it/scientific.php)

This guide does not explain solid state physics and its computational methods. If you want to learn that, read a good textbook.

Codes

PWscf can currently perform the following kinds of calculations:

• ground-state energy and one-electron (Kohn-Sham) orbitals
• atomic forces, stresses, and structural optimization
• molecular dynamics on the ground-state Born-Oppenheimer surface, also with variable-cell
• Nudged Elastic Band (NEB) and Fourier String Method Dynamics (SMD) for energy barriers and reaction paths
• phonon frequencies and eigenvectors at a generic wave vector, using Density-Functional Perturbation Theory
• effective charges and dielectric tensors
• electron-phonon interaction coefficients for metals
• interatomic force constants in real space
• third-order anharmonic phonon lifetimes
• Infrared and Raman (nonresonant) cross section
• macroscopic polarization via Berry Phase

All of the above work for both insulators and metals, in any crystal structure, for many exchange-correlation functionals (including spin polarization and LDA+U), for both norm-conserving (Hamann-Schlüter-Chiang) pseudopotentials in separable form, and -- with very few exceptions -- for Ultrasoft (Vanderbilt) pseudopotentials. Non-colinear magnetism and spin-orbit interactions are also implemented. Finite electric fields are implemented in both the supercell and the ``modern theory of polarization'' approaches (the latter is still at an experimental stage). Various postprocessing and data analysis programs are available.

CP can currently perform the following kinds of calculations:

• Car-Parrinello molecular dynamics simulation
• geometry optimization by damped dynamics
• constant-temperature simulation with Nosè thermostats (including
  Nosè-Hoover chains for each atom)
• variable-cell (Parrinello-Rahman) dynamics
• Nudged Elastic Band (NEB) for energy barriers and reaction paths
• String Method Dynamics (in real space)
• dynamics with Wannier functions and under finite electric fields

Spin-polarized calculations. CP works with both norm-conserving and Ultrasoft pseudopotentials. There are implementations of a dynamics for metals using conjugate-gradient algorithms, and of the meta-GGA functionals. Both are at an experimental stage.

People

The maintenance and further development of the Quantum-ESPRESSO code is promoted by the DEMOCRITOS National Simulation Center of INFM (Italian institute for condensed matter physics) under the coordination of Paolo Giannozzi (Scuola Normale Superiore, Pisa), with the strong support of the CINECA National Supercomputing Center in Bologna under the responsibility of Carlo Cavazzoni. Currently active developers include Gerardo Ballabio (CINECA), Stefano Fabris, Adriano Mosca Conte, Carlo Sbraccia (SISSA, Trieste), Anton Kokalj (Jozef Stefan Institute, Ljubljana).

The PWscf package was originally developed by Stefano Baroni, Stefano de Gironcoli, Andrea Dal Corso (SISSA), Paolo Giannozzi, and others.

The CP code is the result of the merging of two codes: CP and FPMD, both based on the original code written by Roberto Car and Michele Parrinello. CP was developed by Alfredo Pasquarello (IRRMA, Lausanne), Kari Laasonen (Oulu), Andrea Trave (LLNL), Roberto Car (Princeton), Nicola Marzari (MIT), Paolo Giannozzi, and others. FPMD was developed by Carlo Cavazzoni, Gerardo Ballabio (CINECA), Sandro Scandolo (ICTP, Trieste), Guido Chiarotti (SISSA), Paolo Focher, and others.

PWgui was written by Anton Kokalj and is based on his GUIB concept (http://www-k3.ijs.si/kokalj/guib/).

The pseudopotential generation package ``atomic'' was written by Andrea Dal Corso and it is the result of many additions to the original code by Paolo Giannozzi.

The input/output toolkit ``iotk'' was written by Giovanni Bussi (S3, Modena).

An alphabetical list of further contributors includes: Dario Alfè, Francesco Antoniella, Mauro Boero, Nicola Bonini, Claudia Bungaro, Paolo Cazzato, Davide Ceresoli, Gabriele Cipriani, Matteo Cococcioni, Cesar Da Silva, Alberto Debernardi, Gernot Deinzer, Oswaldo Dieguez, Andrea Ferretti, Guido Fratesi, Ralph Gebauer, Martin Hilgeman, Eyvaz Isaev, Yosuke Kanai, Axel Kohlmeyer, Konstantin Kudin, Michele Lazzeri, Kurt Maeder, Francesco Mauri, Nicolas Mounet, Pasquale Pavone, Mickael Profeta, Guido Roma, Manu Sharma, Alexander Smogunov, Kurt Stokbro, Pascal Thibaudeau, Antonio Tilocca, Paolo Umari, Renata Wentzcovitch, Yudong Wu, Xiaofei Wang, and let us apologize to everybody we have forgotten.

This guide was mostly written by Paolo Giannozzi, Gerardo Ballabio, Carlo Cavazzoni.

Contacts

The web site for Quantum-ESPRESSO is:

http://www.quantum-espresso.org/

Releases and patches of Quantum-ESPRESSO can be downloaded from this site or following the links contained in it.

Announcements about new versions of Quantum-ESPRESSO are available via a low-traffic mailing list Pw_users: (pw_users@pwscf.org). You can subscribe (but not post) to this list from the PWscf web site.

The recommended place where to ask questions about installation and usage of Quantum-ESPRESSO, and to report bugs, is the Pw_forum mailing list (pw_forum@pwscf.org). Here you can obtain help from the developers and many knowledgeable users. You can subscribe to this list and browse and search its archive from the PWscf web site. Only subscribed users can post Please search the archives before posting: your question may have already been answered.

If you specifically need to contact the developers of Quantum-ESPRESSO (and only them), write to pwscf@pwscf.org.

Other pointers:
DEMOCRITOS: http://www.democritos.it/
INFM: http://www.infm.it/
CINECA: http://www.cineca.it/
SISSA: http://www.sissa.it/

Terms of use

Quantum-ESPRESSO is free software, released under the GNU General Public License (http://www.pwscf.org/License.txt, or the file License in the distribution).

All trademarks mentioned in this guide belong to their respective owners.

We shall greatly appreciate if scientific work done using this code will contain an explicit acknowledgment and a reference to the Quantum-ESPRESSO web page. Our preferred form for the acknowledgment is the following:

Acknowledgments:
Calculations in this work have been done using the Quantum-ESPRESSO package [ref].

Bibliography:
[ref] S. Baroni, A. Dal Corso, S. de Gironcoli, P. Giannozzi, C. Cavazzoni, G. Ballabio, S. Scandolo, G. Chiarotti, P. Focher, A. Pasquarello, K. Laasonen, A. Trave, R. Car, N. Marzari, A. Kokalj, http://www.pwscf.org/.