ChemSpider

  • Level of openness 3 ★★★
  • Document quality 3 ★★★

ChemSpider is a free chemical structure database that provides fast access to over 100 million structures, properties, and related information, and is operated by the Royal Society of Chemistry.

By integrating and linking compounds from hundreds of high-quality data sources, ChemSpider makes it easy to find chemical data from diverse data sources that are freely available for online searching. Users can also add and manage data in a wikipedia-like fashion. Meanwhile, manual curation by the Royal Society of Chemistry continuously improves data quality.

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MOPAC

  • Level of openness 3 ★★★
  • Document quality 2 ★★☆

An open-source application for semi-empirical quantum chemical calculation based on NDDO (neglect of diatomic differential overlap) approximation. This program calculates, for a given molecule or a crystal, molecular orbits and atomic forces, as well as vibration spectra, thermal quantities (heat of formation etc.), isotopic exchange effect, force constant, and so on. It can also treat radicals and ions.

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PubChem

  • Level of openness 3 ★★★
  • Document quality 2 ★★☆

Open Chemistry database that has been in operation since 2004 under the National Institutes of Health (NIH) in the United States. It mainly targets data for small molecules, but information on large molecules such as lipids and peptides are also collected. The database can be accessed via web browser or PUG REST API. The data can be also downloaded from an FTP site.

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QCMaquis

  • Level of openness 3 ★★★
  • Document quality 3 ★★★

An open-source application for obtaining optimized many-body wavefunctions expressed by matrix product states (MPS). By using a second-generation density matrix renormalization group (DMRG) algorithm, many-body wave functions can be efficiently optimized. The quantum-chemical operators are represented by matrix product operators (MPOs), which provides flexibility to accommodate various symmetries and relativistic effects.

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SMASH

  • Level of openness 3 ★★★
  • Document quality 1 ★☆☆

Open source software for massively parallel quantum chemistry calculations. Energies and geometries of nano-sized molecules can be calculated without fragmentation. The program supports Hartree-Fock, density functional theory, and second-order Møller-Plesset perturbation theory calculations. The input format, execution method, and program structure are simple, and frequently used routines can be easily extracted.

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PubChemPy

  • Level of openness 3 ★★★
  • Document quality 2 ★★☆

Python code for a chemical database, PubChem. Users can search data in PubChem by compound name, structural information and so on. It is also possible to receive outputs as a Pandas DataFrame.

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k-ep

  • Level of openness 3 ★★★
  • Document quality 1 ★☆☆

Fortran codes for computing the specified k-th eigenvalue and eigenvector for generalized symmetric definite eigenvalue problems. Sylvester’s law of inertia is employed as the fundamental principle in computations, and the sparse direct linear solver (MUMPS) is used in the main routine. By inputting Hamiltonian and its overlap matrices, user can compute electron’s energy and its wave function in the specified k-th energy level.

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NWChem

  • Level of openness 3 ★★★
  • Document quality 2 ★★☆

An open-source application for general-purpose quantum chemical calculation, laying emphasis on excited states and time evolution. It is based on time-dependent density functional theory (TDDFT) and the QM/MM calculation. It enables efficient massive parallel computing up to one hundred thousands processes. It supports the relativistic effect and offers the basis choice between the Gaussian basis and the plane-wave basis.

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SIMPLE-NN

  • Level of openness 3 ★★★
  • Document quality 2 ★★☆

Software package to implement Behler-Parinello neural network potentials. Potentials can be trained from structure-energy/ interatomic forces/stress data, and molecular dynamics calculations using LAMMPS can also be performed using learned potentials. A prediction uncertainty measure can also be calculated simultaneously.

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PFAPACK

  • Level of openness 3 ★★★
  • Document quality 2 ★★☆

Library for calculating Pfaffian (square root of determinant), which is defined for skew-symmetric matrices. Algorithms are implemented in several languages (Fortran, Python, Matlab, Mathematica) and users can choose favorite one. Interfaces for C are also provided.

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