Quantum ESPRESSO is a suite for
first-principles electronic-structure calculations and materials modeling, distributed for free and as
free software
Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, ...
under the
GNU General Public License
The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end user
In product development, an end user (sometimes end-user) is a person who ultimately uses or is intended to ulti ...
. It is based on
density-functional theory
Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-b ...
,
plane wave
In physics, a plane wave is a special case of wave or field: a physical quantity whose value, at any moment, is constant through any plane that is perpendicular to a fixed direction in space.
For any position \vec x in space and any time t, t ...
basis sets, and
pseudopotential
In physics, a pseudopotential or effective potential is used as an approximation for the simplified description of complex systems. Applications include atomic physics and neutron scattering. The pseudopotential approximation was first introduced ...
s (both norm-conserving and ultrasoft). ESPRESSO is an acronym for opEn-Source Package for Research in Electronic Structure, Simulation, and Optimization.
The core
plane wave
In physics, a plane wave is a special case of wave or field: a physical quantity whose value, at any moment, is constant through any plane that is perpendicular to a fixed direction in space.
For any position \vec x in space and any time t, t ...
DFT functions of QE are provided by the PWscf component (PWscf previously existed as an independent project). PWscf (Plane-Wave Self-Consistent Field) is a set of programs for
electronic structure
In quantum chemistry, electronic structure is the state of motion of electrons in an electrostatic field created by stationary nuclei. The term encompasses both the wave functions of the electrons and the energies associated with them. Elec ...
calculations within
density functional theory
Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-bo ...
and density functional perturbation theory, using
plane wave
In physics, a plane wave is a special case of wave or field: a physical quantity whose value, at any moment, is constant through any plane that is perpendicular to a fixed direction in space.
For any position \vec x in space and any time t, t ...
basis sets and
pseudopotential
In physics, a pseudopotential or effective potential is used as an approximation for the simplified description of complex systems. Applications include atomic physics and neutron scattering. The pseudopotential approximation was first introduced ...
s. The software is released under the
GNU General Public License
The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end user
In product development, an end user (sometimes end-user) is a person who ultimately uses or is intended to ulti ...
.
The latest version QE-7.1 was released on 16 June 2022.
Quantum ESPRESSO Project
Quantum ESPRESSO is an open initiative of the CNR-IOM DEMOCRITOS National Simulation Center in
Trieste
Trieste ( , ; sl, Trst ; german: Triest ) is a city and seaport in northeastern Italy. It is the capital city, and largest city, of the autonomous region of Friuli Venezia Giulia, one of two autonomous regions which are not subdivided into pr ...
(
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...
) and its partners, in collaboration with different centers worldwide such as
MIT,
Princeton University
Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the n ...
, the
University of Minnesota
The University of Minnesota, formally the University of Minnesota, Twin Cities, (UMN Twin Cities, the U of M, or Minnesota) is a public university, public Land-grant university, land-grant research university in the Minneapolis–Saint Paul, Tw ...
and the
École Polytechnique Fédérale de Lausanne
École may refer to:
* an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée)
* École (river), a tributary of the Seine
The Seine ( , ) is a river in northern Franc ...
. The project is coordinated by the QUANTUM ESPRESSO foundation, which was formed by many research centers and groups all over the world. The first version, called ''pw.1.0.0'', was released on 15-06-2001.
The program, written mainly in
Fortran-90 with some parts in
C or in Fortran-77, was built out of the merging and re-engineering of different independently developed core packages, plus a set of packages, designed to be inter-operable with the core components, which allow more advanced tasks to be performed.
The basic packages include ''Pwscf'', which solves the self-consistent
Kohn-Sham equations, obtained for a periodic solid, ''CP'' to carry out
Car-Parrinello molecular dynamics, and ''PostProc'', which allows data analysis and plotting. Regarding the additional packages, is noteworthy to point out ''atomic'' for the pseudopotential generation, ''PHonon'' package, which implements density-functional perturbation theory (DFPT) for the calculation of second- and third-order derivatives of the energy with respect to atomic displacements, and ''NEB'' (nudged elastic band): for the calculation of reaction pathways and energy barriers.
Target problems
The different tasks that can be performed include
* Ground state calculations
* Structural optimization
* Transition states and minimum energy paths
* Response properties (DFPT), such as phonon frequencies, electron-phonon interactions and
EPR and
NMR chemical shifts
* ''Ab initio'' molecular dynamics:
Car-Parrinello and Born-Oppenheimer MD
* Spectroscopic properties
* Quantum import
* Generation of pseudopotentials
Parallelization
The main components of the Quantum ESPRESSO distribution are designed to exploit the architecture of today's supercomputers characterized by multiple levels and layers of inter-processor communication. The parallelization is achieved using both
MPI and
OpenMP
OpenMP (Open Multi-Processing) is an application programming interface (API) that supports multi-platform shared-memory multiprocessing programming in C, C++, and Fortran, on many platforms, instruction-set architectures and operating sy ...
parallelization, allowing the main codes of the distribution to run in parallel on most or all parallel machines with very good performance.
See also
*
Quantum chemistry computer programs
Quantum chemistry computer programs are used in computational chemistry to implement the methods of quantum chemistry. Most include the Hartree–Fock (HF) and some post-Hartree–Fock methods. They may also include density functional theory (DF ...
*
Density Functional Theory
Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-bo ...
References
External links
Website of Quantum ESPRESSOWebsite of Quantum ESPRESSO Foundation (QEF)
{{Chemistry software
Computational chemistry software
Computational physics
Density functional theory software
Free science software
Physics software