Projects / Siam Quantum

Siam Quantum (SQ) is a quantum chemistry program that calculates wave function and total energy of molecules. It currently supports Hartree-Fock and MP2 methods using Gaussian-type basis functions. Geometry optimization is also possible. The source code is well documented because it was initially designed for academic purposes so that students can easily understand. However, Siam Quantum can also produce high quality results for research purposes because the energies calculated are comparable to the ones produced by other software packages such as Gaussian or GAMESS, with the errors in the order of 10^-6 Hartrees, which can be further reduced with more strict cut-off.

Tags | Quantum Mechanics Quantum Chemistry |
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Licenses | GPL |

Operating Systems | Linux Windows |

Implementation | C |

Translations | English Thai |

- 22 Mar 2013 06:11

**Release Notes:** The Minimum Energy Crossing Point (MECP) between two spin states can now be calculated.

- 09 Mar 2013 23:32

**Release Notes:** MP2 mode is now much faster and requires little storage.
The speed enhancement is achieved by multiple approximations and the support for parallel
runs under HF,
OPT,
and MP2 modes.

- 01 Dec 2012 06:59

**Release Notes:** Electron correlation energy using Moller-Plesset perturbation theory (MP2) is now available. Calculated results can now be stored in a checkpoint file. The bug related to DIIS convergence method has been fixed.

- 07 Jun 2011 08:49

**Release Notes:** This minor performance improvement release stores integration results in memory in order to be reused in the next iterative cycle instead of re-calculating them. DIIS method has been implemented, allowing the iterations to converge to a solution faster.

- 22 Oct 2010 12:57

**Release Notes:** Geometry optimization and population analysis are now available. The calculation of forces acting on nuclei within a molecule was implemented, which makes it possible to predict the three dimensional structure of the molecule using only a fundamental equation of quantum mechanics, the Schrödinger equation.