SIESTA (computer program)
SIESTA (Spanish Initiative for Electronic Simulations with Thousands of Atoms) is an original method and its computer program implementation, to perform efficient electronic structure calculations and ab initio molecular dynamics simulations of molecules and solids. SIESTA's efficiency stems from the use of strictly localized basis sets and from the implementation of linear-scaling algorithms which can be applied to suitable systems. A very important feature of the code is that its accuracy and cost can be tuned in a wide range, from quick exploratory calculations to highly accurate simulations matching the quality of other approaches, such  as plane-wave and all-electron methods. SIESTA's backronym is Spanish Initiative for Electronic Simulations with Thousands of Atoms. Since 13 May 2016, with the 4.0 version announcement, SIESTA is released under the terms of the GPL open-source license. Source packages and access to the development versions can be obtained from the DevOps platform on GitLab. The latest version Siesta-4.1.5 was released on 4 February 2021. Features. SIESTA has these main characteristics: SIESTA routinely provides: And also (though not all options are compatible): Strengths of SIESTA. SIESTA main strengths are: The use of linear combination of numerical atomic  orbitals makes SIESTA a flexible and efficient DFT code. SIESTA is able to produce very fast calculations with small basis sets, allowing computing systems with a thousand of atoms. At the same time, the use of more complete and accurate bases allows to achieve accuracies comparable to those of standard plane waves calculations, still at an advantageous computational cost. Implemented Solutions. SIESTA is in continuous development since it was implemented in 1996. The main solutions implemented in the current version are: Post-processing tools. A number of post-processing tools for SIESTA have been developed. These programs can be helpful  to process SIESTA output, or to supplement the functionality of the program. Applications. Since its implementation, SIESTA has become quite popular, being increasingly used by researchers in geosciences, biology, and engineering (apart from those in its natural habitat of materials physics and chemistry) and has been applied to a large variety of systems including surfaces, adsorbates, nanotubes, nanoclusters, biological molecules, amorphous semiconductors, ferroelectric films, low-dimensional metals, etc.