SIESTA (computer program): Difference between revisions

Revision as of 13:02, 22 March 2023

Revision as of 22:12, 16 June 2023

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* It uses norm-conserving [[pseudopotential]]s in their fully non-local (Kleinman-Bylander) form.

* It uses [[atomic orbital]]s as a basis set, allowing unlimited multiple-zeta and angular momenta, polarization and off-site orbitals. The radial shape of every orbital is numerical, and any shape can be used and provided by the user, with the only condition that it has to be of finite support, i.e., it has to be strictly zero beyond a user-provided distance from the corresponding nucleus. Finite-support basis sets are the key to calculating the Hamiltonian and overlap matrices in O(N) operations.

* Projects the electron wavefunctionswave functions and density onto a real-space grid in order to calculate the Hartree and exchange-correlation potentials and their matrix elements.

* Besides the standard Rayleigh-Ritz eigenstate method, it allows the use of localized linear combinations of the occupied orbitals (valence-bond or Wannier-like functions), making the computer time and memory scale linearly with the number of atoms. Simulations with several hundred atoms are feasible with modest workstations.

* It is written in [[Fortran 95]] and memory is allocated dynamically.

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== Applications ==

Since its implementation, SIESTA has been used by researchers in geosciences, biology, and engineering (extending beyond materials physics and chemistry) and has been applied to a large variety of systems including surfaces, adsorbates, nanotubes, nanoclustersnano clusters, biological molecules, amorphous semiconductors, ferroelectric films, low-dimensional metals, etc.<ref>Mashaghi A et al. Hydration strongly affects the molecular and electronic structure of membrane phospholipids J. Chem. Phys. 136, 114709 (2012) [http://scitation.aip.org/content/aip/journal/jcp/136/11/10.1063/1.3694280]</ref><ref>Mashaghi A et al. Interfacial Water Facilitates Energy Transfer by Inducing Extended Vibrations in Membrane Lipids, J. Phys. Chem. B, 2012, 116 (22), pp 6455–6460 [http://pubs.acs.org/doi/abs/10.1021/jp302478a]</ref><ref>Mashaghi A et al. Enhanced Autoionization of Water at Phospholipid Interfaces. J. Phys. Chem. C, 2013, 117 (1), pp 510–514 [http://pubs.acs.org/doi/abs/10.1021/jp3119617]</ref>

== See also ==