Qbox home page

Welcome to qboxcode.org, home of the Qbox first-principles molecular dynamics code.

Qbox is a C++/MPI scalable parallel implementation of first-principles molecular dynamics (FPMD) based on the plane-wave, pseudopotential formalism. Qbox is designed for operation on large parallel computers.

New Join us on Slack at https://qboxcode.slack.com

Qbox is now available on the GitLab server
http://scherzo.ucdavis.edu/qbox/qbox-public

It is also available on github at https://github.com/qboxcode

[2021-08-20] Version 1.73.3 is available.
This is a bugfix release.

[2021-02-24] Version 1.73.1 is available.
This release includes a new Anderson accelerated IonicStepper.

[2020-09-24] Version 1.72.0 is available.
This release includes a complete rewrite of the data layout used in the representation of wave functions, leading to a substantial acceleration of simulations involving multiple k-points, or spin-polarized simulations. It introduces the -nstb, -nkpb and -nspb command line options that control the shape of the MPI process grid. The nrowmax variable is deprecated.

[2020-07-10] Version 1.71.4 is available.
This bugfix release fixes an issue encountered when running on a single task, or with nrowmax==1, and with a non-cubic unit cell. The issue affects releases 1.71.[23] only.

[2020-05-08] Version 1.71.0 is available.
This release changes the sign convention of the forces acting on constraints, so that a positive force corresponds to a decreasing energy in the direction of increasing constraint value. The release also fixes a bug in the update of variable constraints that affected continuity of constraint values across multiple MD simulations.

[2020-05-08] Version 1.70.0 is available.
This release includes arbitrary electronic occupation numbers for delta-SCF calculations.

[2020-05-02] Version 1.69.1 is available.
This release includes the calculation of optical absorption spectra in the independent particle approximation.

[2020-02-04] Version 1.68.2 is available.
This release fixes issues arising with the SCAN functional when the density gradient is exactly zero after initialization with atomic densities.

[2019-09-17] Version 1.68.0 is available.
This release includes the SCAN meta-GGA density functional.

[2019-06-19] Version 1.67.4 is available.
This release enables the use of pseudopotentials that include a non-linear core correction. Potentials of the pseudo-dojo collection http://pseudo-dojo.org can be used by translating them from UPF format to QSO format using the upf2qso program provided in the Qbox distribution in the util directory.

[2019-03-24] Version 1.66.3 is available. This release includes improved atomic charge parameters and self-consistent iteration parameters leading to faster initial ground state calculations. Recent features include the calculation of polarizability in constant or arbitrary external fields, range-separated and HSE hybrid functionals and the BHandHLYP functional, the implementation of the B3LYP functional for spin-polarized systems, calculations of the partial charge/spin in atom-centered spheres, and the option to execute arbitrary commands at regular intervals during MD simulations. Recent features also include simulations in the presence of a constant finite electric field. Optimized Norm-Conserving Vanderbilt (ONCV) pseudopotentials were enabled in version 1.62.3.

The SG15 collection of ONCV pseudopotentials is available at http://www.quantum-simulation.org. The SG15 potentials were optimized to reproduce all-electron calculations with high accuracy. The potentials are described in M. Schlipf and F. Gygi, Comput. Phys. Comm. 196, 36-44 (2015) http://dx.doi.org/10.1016/j.cpc.2015.05.011.

Documentation

See online documentation.
The design of Qbox is discussed in the following architecture paper (IBM J. Res. Dev. 52 p.137 (2008)).

Building Qbox

build instructions.

Qbox tools

A set of tools is available for post-processing and visualization of Qbox output.

Qbox output format

Qbox output conforms to the XML Schema described at http://www.quantum-simulation.org. This format is supported by the NOMAD repository https://repository.nomad-coe.eu

Qbox forum

A forum dedicated to questions regarding Qbox installation and use is available at http://qboxcode.org/qbox-list

Acknowledgement

Qbox is developed and maintained at the University of California Davis. Development is currently supported by a collaboration with the DOE Midwest Integrated Center for Computational Materials. Previous support was provided by the U.S. Department of Energy, Office of Basic Energy Sciences under grant DE-SC0008938.