Quantum ESPRESSO (Quantum Open-Source Package for Research in Electronic Structure, Simulation, and Optimization; QE) is a suite for first-principles electronic-structure calculations and materials modeling, distributed for free and as

free software Free software, libre software, libreware sometimes known as freedom-respecting software is computer software distributed open-source license, under terms that allow users to run the software for any purpose as well as to study, change, distribut ...

under the

GNU General Public License The GNU General Public Licenses (GNU GPL or simply GPL) are a series of widely used free software licenses, or ''copyleft'' licenses, that guarantee end users the freedom to run, study, share, or modify the software. The GPL was the first ...

. 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 ...

(DFT),

plane wave In physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of ...

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 introduce ...

s (both norm-conserving and ultrasoft). 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 Quantum chemistry, also called molecular quantum mechanics, is a branch of physical chemistry focused on the application of quantum mechanics to chemical systems, particularly towards the quantum-mechanical calculation of electronic contributions ...

calculations within DFT and density functional perturbation theory, using

basis sets and

s. The software is released under the

. The latest stable version QE-7.4.1 was released on 14 March 2025.

Quantum ESPRESSO Project

Quantum ESPRESSO is an open initiative of the CNR-IOM DEMOCRITOS National Simulation Center in

Trieste Trieste ( , ; ) is a city and seaport in northeastern Italy. It is the capital and largest city of the Regions of Italy#Autonomous regions with special statute, autonomous region of Friuli-Venezia Giulia, as well as of the Province of Trieste, ...

(

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

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

MIT The Massachusetts Institute of Technology (MIT) is a private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of modern technology and sc ...

Princeton University Princeton University is a private university, private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial ...

, the

University of Minnesota The University of Minnesota Twin Cities (historically known as University of Minnesota) is a public university, public Land-grant university, land-grant research university in the Minneapolis–Saint Paul, Twin Cities of Minneapolis and Saint ...

and the

École Polytechnique Fédérale de Lausanne The École Polytechnique Fédérale de Lausanne (, EPFL) is a public university, public research university in Lausanne, Switzerland, founded in 1969 with the mission to "train talented engineers in Switzerland". Like its sister institution E ...

. 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 is written mainly in Fortran-90 with some parts in C or in Fortran-77. It is composed of a set of core components, a set of plug-ins for advanced tasks, and a set of third-party packages. 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. Noteworthy additional packages include ''atomic'' for pseudopotential generation, ''PHonon'' for density-functional perturbation theory (DFPT) and 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 state In chemistry, the transition state of a chemical reaction is a particular configuration along the reaction coordinate. It is defined as the state corresponding to the highest potential energy along this reaction coordinate. It is often marked w ...

s 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 atomic nucleus, nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near and far field, near field) and respond by producing ...

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, which are characterized by multiple levels and layers of inter-processor communication. Parallelization is achieved using both

MPI MPI or Mpi may refer to: Science and technology Biology and medicine * Magnetic particle imaging, a tomographic technique * Myocardial perfusion imaging, a medical procedure that illustrates heart function * Mannose phosphate isomerase, an enzyme ...

and

OpenMP OpenMP 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 systems, including Solaris, ...

, allowing the main codes of the distribution to run in parallel on most or all parallel machines with very good performance. In recent years of development, Quantum ESPRESSO has increasingly adopted

CUDA In computing, CUDA (Compute Unified Device Architecture) is a proprietary parallel computing platform and application programming interface (API) that allows software to use certain types of graphics processing units (GPUs) for accelerated gene ...

-basec

GPU A graphics processing unit (GPU) is a specialized electronic circuit designed for digital image processing and to accelerate computer graphics, being present either as a discrete video card or embedded on motherboards, mobile phones, personal ...

acceleration across the different tools to improve 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