MOLGW
is a code that implements the many-body perturbtation theory (MBPT) to describe the excited electronic states in finite systems (atoms, molecules, clusters).
It most importantly implements the GW approximation for the self-energy and the Bethe-Salpeter equation for the optical excitations.

MOLGW
comes with a fully functional density-functional theory (DFT) code to prepare the subsequent MBPT runs.
Standard local and semi-local approximations to DFT are available, as well as several hybrid functionals and range-separated hybrid functionals.
MOLGW uses a Gaussian-type orbitals basis set so to reuse all the standard quantum-chemistry tools.

In parallel,
MOLGW
can straightforwardly calculate systems containing about 100 atoms
or, in terms of basis functions, systems requiring about 2000 basis functions.
Larger calculations are of course feasible, but require large computers, lots of memory, and some patience...

MOLGW: Who can use it?

Anyone!

MOLGW is an open-source software released under the GNU Public License version 3.0.
And as such, MOLGW is completely free of charge.
The GNU Public License offers the possibility for the user to download, compile, modify, and even redistribute the code.

MOLGW: What can it do?

MOLGW is a Gaussian-type orbital code for finite systems.
It implements a self-consistent mean-field calculation, followed by a many-body perturbtation theory post-treatment.

MOLGW can run a wide variety of popular density-functional theory approximations, including: