Advertised Version: 4.0b4 Continuous Version: 1.0b4 Release Date: 7 Apr 2013 Documentation: http://psicode.org/psi4manual/4.0b4/ Availability: Public, Sourceforge source, Autotools build, No binary

The first public beta release includes all-new, very efficient density-fitted, shared-memory parallel code for Hartree-Fock, DFT, and MP2, and symmetry-adapted perturbation theory (SAPT). We also add new code for MP4, QCISD(T), and G2. New modules performing frozen natural orbital coupled-cluster have been added. Previous PSI3 functionality for coupled-cluster energies and properties, and arbitrary-order CI and MBPT energies is also available. A completely new, very user-friendly input format has been implemented, and it can be (optionally) mixed with Python to allow automation of very complex tasks with simple input files. Built-in routines to handle counterpoise correction and basis set extrapolation are included.

The Beta4 release is the first public version. The latest accomplishments are:

• Frozen Natural orbital CCSD(T) code available
• RHF MP4, QCISD(T), and G2 features added
• dlDF-D available
• Interface to WebMO completed
• General framework for double-hybrid functionals, with several added such as B2PLYP
• More efficient Density Cumulant Functional Theory (DCFT) code with analytic gradients working
• Production-level DFT code implemented for GGA, LRC, and Meta functionals.
• Production-level DF-MP2 code working with RHF, UHF, ROHF references
• ADC(2) propagator code working
• CC gradients, CC response, CI energies, MP(n) energies, ZAPT(n) energies, EOM-CC excitation energies, CC3 energies working
• Extremely efficient, threaded SAPT code completed
• User-friendly interface to Kallay’s MRCC code
• Interface to PubChem to allow chemical names in lieu of coordinates in molecule inputs