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, no ...

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 users the Four Freedoms (Free software), four freedoms to run, study, share, and modify the software. The license was th ...

. 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-body s ...

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, th ...

basis sets Basis may refer to: Finance and accounting *Adjusted basis, the net cost of an asset after adjusting for various tax-related items *Basis point, 0.01%, often used in the context of interest rates *Basis trading, a trading strategy consisting of ...

, 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

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. Electro ...

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-body ...

and density functional perturbation theory, using

and

s. The software is released under the

. 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 provi ...

(

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 re ...

) and its partners, in collaboration with different centers worldwide such as

MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the mo ...

Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...

, 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 flowing in région Île-de-France * École, Savoi ...

. 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 Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with a ...

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 syste ...

parallelization, allowing the main codes of the distribution to run in parallel on most or all parallel machines with very good performance.

References

External links

Website of Quantum ESPRESSO

Website of Quantum ESPRESSO Foundation (QEF)
{{Chemistry software Computational chemistry software Computational physics Density functional theory software Free science software Physics software

Quantum ESPRESSO Project

Target problems

Parallelization

See also

References

External links