MPQC3 is an ab-inito quantum chemistry program. It is especially designed to compute molecules in an explicitly-correlated fashion.

It can compute energies and gradients for the following methods:
* Hartree-Fock (HF)
* Density Functional Theory (DFT)
* Second-order Moeller-Plesset pertubation theory (MP2)
Additionally, it can compute energies for the following methods:
* Local MP2 (LMP2)
* Explicitly-correlated density-fitted MP2 (DF-MP2-F12)
* Explicitly-correlated density-fitted coupled-cluster singles doubles
(DF-CCSD-F12)
* Explicitly-correlated density-fitted coupled-cluster singles doubles with
perturbative triples (DF-CCSD(T)-F12)
* Explicitly-correlated density-fitted complete active space SCF
(DF-CASSCF-F12)
* Explicitly-correlated density-fitted multi-reference configuration
interaction (DF-MRCI-F12)
It also includes an internal coordinate geometry optimizer.