The QuantumChemistry package is an environment for computing and visualizing the quantum energies and properties of many-electron atoms and molecules.     

The geometries of molecules can be entered interactively by the user, read from a file, or obtained from a web database containing geometries of more than 96 million molecules.  

Advanced wavefunction, density functional, and reduced density matrix methods are available for computing atomic and molecular energies and properties.

Molecular geometries, densities, and vibrations can be visualized in 3D interactive plots and animations.

Commands can be accessed from a Maple worksheet or document, the command-line interface, or an Interactive Maplet.

Lessons and curricula for chemistry and physics courses, which are directly integrated into the package, can be used for formal courses as well as self study.

For an introductory tutorial, see the QuantumChemistry Package Tutorial Worksheet.

Each command in the QuantumChemistry package can be accessed by (1) loading all of the commands in the package through the command with(QuantumChemistry) and (2) calling each command as Command(arguments) with appropriate arguments as described in the command's help page.  See the short form for additional details.

Each command in the QuantumChemistry package can be accessed by calling the package name and the command name in either of the formats: (1)  QuantumChemistry[Command](arguments) or (2) QuantumChemistry:-Command(arguments) with appropriate arguments as described in the command's help page.  See the long form for additional details.    

The QuantumChemistry package resets Maple's default precision display from all decimals available to 8 decimals.  The package's precision display can be changed from 8 (default) to 10 by issuing the command QuantumChemistry(displayprecision=10).

This displayprecision affects only the number of digits displayed; the precision of the floating-point arithmetic is set by assigning the environmental variable Digits to an integer representing the number of significant digits; for example, Digits := 15 sets the number of significant digits to 15.  The default setting of Digits in Maple is 10; for the QuantumChemistry package it is recommended that Digits be assigned to 15 for double precision.

The QuantumChemistry package resets Maple's default display of Matrices and Matrix slices from [10,10] to [6,6].  The package's matrix display can be changed from [6,6] (the package's default) to [10,10] (Maple's default) by issuing the command QuantumChemistry(displaymatrix=[10,10]).  

On the Windows operating system the commands CoupledCluster, NuclearGradient, and RDMFunctional require the installation of Microsoft's Windows Subsystem for Linux (WSL).  The WSL can be installed before or after installation of the QuantumChemistry package.  For Windows 10 (version 2004 and higher) and Windows 11 you can install the WSL by opening the Command Prompt in administrator mode and entering the command: wsl --install -d Ubuntu  For additional details, please refer to: https://learn.microsoft.com/en-us/windows/wsl/install

D. J. Griffiths and D. F. Schroeter, Introduction to Quantum Mechanics 3rd Edition (Cambridge University Press, 2018).

F. Jensen, Introduction to Computational Chemistry 3rd Edition (John Wiley & Sons, New York, 2017).

I. N. Levine, Quantum Chemistry 7th Edition (Pearson, New York, 2017).

J. J. Sakurai and J. Napolitano, Modern Quantum Mechanics 2nd Edition (Cambridge University Press, Cambridge, 2017).

J. P. Lowe, Quantum Chemistry Illustrated Edition (Academic Press, New York, 2012).

P. W. Atkins, J. de Paula, and J. Keeler, Physical Chemistry 12 Edition (Oxford University Press, Oxford, 2023).

P. W. Atkins and R. S. Friedman, Molecular Quantum Mechanics 5th Edition (Oxford University Press, Oxford, 2010).

C. Cramer, Essentials of Computational Chemistry: Theories and Models 2nd Edition (John Wiley & Sons, New York, 2007).

D. A. McQuarrie, Quantum Chemistry 2nd Edition (University Science, New York, 2007).

Reduced Density Matrix Mechanics with Applications to Atoms and Molecules, Volume 134 in the Advances in Chemical Physics series, edited by D. A. Mazziotti  (John Wiley & Sons, New York, 2007).

T. Helgaker, P. Jorgensen, and J. Olsen, Molecular Electronic-Structure Theory (John Wiley & Sons, New York, 2000).

D. A. McQuarrie and J. D. Simon, Physical Chemistry: A Molecular Approach (University Science, New York, 1997).

A. Szabo and N. S. Ostlund, Modern Quantum Chemistry: Introduction to Advanced Electronic Structure Theory (Dover Books, New York, 1996).
D. A. Mazziotti, Chem. Rev. 112, 244 (2012). "Two-electron reduced density matrix as the basic variable in many-electron quantum chemistry and physics"

Q. Sun, T. C. Berkelbach, N. S. Blunt, G. H. Booth, S. Guo, Z. Li, J. Liu, J. D. McClain, E. R. Sayfutyarova, S. Sharma, S. Wouters, and G. K.-L. Chan, WIRES Computational Molecular Science 8, 1340 (2018). "PySCF: the Python‐based simulations of chemistry framework"

$\mathrm{with}\left(\mathrm{QuantumChemistry}\right)\:$

$\mathrm{molecule} ≔ \left[\left[''H''\,0\,0\,0\right]\,\left[''F''\,0\,0\,0.95\right]\right]\;$

$\mathrm{molecule}≔\left[\left[''H''\,0\,0\,0\right]\,\left[''F''\,0\,0\,0.95000000\right]\right]$

$\mathrm{output} ≔ \mathrm{HartreeFock}\left(\mathrm{molecule}\, \mathrm{basis}\=''dz''\right)\;$

$\mathrm{output} ≔ \mathrm{Parametric2RDM}\left(\mathrm{molecule}\, \mathrm{basis}\=''dz''\right)\;$