QCElemental

QCElemental is a resource module for quantum chemistry (QC) containing physical constants and periodic table data from NIST. It also contains molecule handlers (suitable for QC parsing and input files) and the QC data exchange format known as QCSchema.

Physical Constants

Physical constants can be acquired directly from the NIST CODATA:

>>> qcel.constants.get("hartree energy in ev")
27.21138602

Alternatively, with the use of the Pint unit conversion package, arbitrary conversion factors can be obtained:

>>> qcel.constants.conversion_factor("bohr", "miles")
3.2881547429884475e-14

Periodic Table Data

A variety of periodic table quantities are available using virtually any alias:

>>> qcel.periodictable.to_mass("Ne")
19.9924401762

>>> qcel.periodictable.to_mass(10)
19.9924401762

Molecule Handlers

Molecules can be translated to/from the MolSSI QCSchema format or quantum chemistry program specific input specifications such as NWChem, Psi4, and CFour. In addition, databases such as PubChem can be searched:

>>> qcel.molparse.from_string("pubchem:benzene")
    Searching PubChem database for benzene (single best match returned)
    Found 1 result(s)
    {"geometry": ...}

Index

Getting Started

QCSchema Models

Implementation descriptions of QCSchema objects in Python.

Quantities

Developer Documentation

Contains in-depth developer documentation and API references.

Indices and tables