MPQC is the Massively Parallel Quantum Chemistry Program. It computes properties of atoms and molecules from first principles using the time independent Schrödinger equation. It runs on a wide range of architectures ranging from individual workstations to symmetric multiprocessors to massively parallel computers. Its design is object oriented, using the C++ programming language.

Here are some key features of "MPQC":

· Closed shell, unrestricted and general restricted open shell Hartree-Fock energies and gradients
· Closed shell, unrestricted and general restricted open shell density functional theory energies and gradients
· Second order open shell perturbation theory (OPT2[2]) and Z-averaged perturbation theory (ZAPT2) energies.
· Second order closed shell M?ller-Plesset perturbation theory energies and gradients.
· Second order M?ller-Plesset perturbation theory including an R12 correlation factor using an auxilary basis set [(ABS) MP2-R12]. Energies of closed-shell systems are supported.
· Robust internal coordinate geometry optimizer that efficiently optimizes molecules with many degrees of freedom. Nearly arbitrary internal coordinate constraints can be handled.


Whats New in This Release:

· Common Component Architecture interfaces for energies and integrals are now available.
· Updated to a more recent version of the EMSL basis sets. This will change results in many cases.
· Polarization consistent basis sets added.
· Test suite inputs and results have been moved from a separate file into the main release.
· "make" targets are now available to automatically check results.
· "mpqcrun" can be used to simply starting MPQC runs, particulary parallel runs.
· Complementary Auxiliary Basis Set (CABS) version of the MP2-R12 method [see Chem. Phys. Lett. 395, 190 (2004)].
· MP2-R12/A method with split virtual space (virtual orbitals constructed from a separate Gaussian basis).
· Novel Brillouin condition-free versions of the MP2-R12/A method.
· A new exception infrastructure has been added.
· Numerous numerical improvements, compiler bug work-arounds, and bug fixes.
· Checkpoint files made with earlier versions of MPQC utilizing more than one processor will not work 2.3.0 or later versions.