Quantum-ESPRESSO

Author

A list of authors can be found in the documentation or from the official web site (http://www.quantum-espresso.org).

Origin

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

Version

Quantum-ESPRESSO 4.0 & 3.2.3

Official Web Site

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

Brief Program Description

The Quantum-ESPRESSO package is an integrated suite of computer codes for electronic-structure calculations and materials modeling at the nanoscale. It is based on density-functional theory, plane waves, and pseudopotentials (both norm-conserving and ultrasoft). It contains a plane-wave self consistent field code (PWscf) and a Car-Parinello code (CP). These can be used to calculate electronic structure properties within density functional theory using a plane wave basis set and pseudopotentials.

Areas of Application

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), for both norm-conserving (Hamann-Schlutter-Chiang) pseudopotentials in separable form, and - with very few exceptions - for ultrasoft (Vanderbilt) pseudopotentials. Non-colinear magnetism and spin- orbit interactions are also implemented, although at an experimental stage. Various postprocessing programs are available.

CP can currently perform the following kinds of calculations:

• Car-Parinello molecular dynamics simulation

• geometry optimization by damped simulation

• constant-temperature simulation with Nose thermostats

• variable-cell (Parinello-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

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

Implementation and Access

Quantum-ESPRESSO 4.0 is available on Magellan and can be accessed by the command as follows:

$CHEM/runespresso40 program < inputfile > outputfile

Quantum-ESPRESSO runs both in serial and in parallel. Users should refer to the man page (runespresso40) for details for further information on how to use the code.

Version 3.2.3 is still the default and is available on Magellan and can be accessed by the runscript runespresso. The man page for version 3.2.3 is runespresso.

Machines

Available on Magellan.

Documentation

The Quantum-ESPRESSO User Guide is available as a PDF file from the directory $CHEM/doc/espresso/espresso-3.2/Doc for version 3.2.3 and $CHEM/doc/espresso/espresso-4.0/Doc for version 4.0. This directory also contains a number of files INPUT_XX which summarise the available input variables and cards. A set of example input and output files can be found in the directory $CHEM/doc/espresso/examples.

Further information can also be found on the Quantum-ESPRESSO website:

http://www.quantum-espresso.org

and the PWscf website:

http://www.pwscf.org

Information on how to run Quantum-ESPRESSO jobs may be found in the online man page, accessible by typing: man runespresso .

There is also a Unix-style man page for version 3.2.1, accessible by typing: man runespresso321

Literature References

References on the general background and methods used are given on the Quantum-ESPRESSO web site.

Specialist Support

N/A

Program Restrictions and Comments

N/A