Pakket: psi3 (3.4.0-6build2)

Quantum Chemical Program Suite

PSI3 is an ab-initio quantum chemistry program. It is especially designed to accurately compute properties of small to medium molecules using highly correlated techniques.

It can compute energies and gradients for the following methods:

 * Closed shell and general restricted open shell Hartree-Fock (RHF/ROHF)
   (including analytical hessians for RHF)
 * Closed shell Moeller-Plesset pertubation theory (MP2)
 * Complete active space SCF (CASSCF)
 * Coupled-cluster singles doubles (CCSD)
 * Coupled-cluster singles doubles with pertubative triples (CCSD(T))
   (only for unrestricted (UHF) reference wavefunctions)

Additionally, it can compute energies for the following methods:

 * Unrestricted open shell Hartree-Fock (UHF)
 * Closed/open shell Moeller-Plesset pertubation theory (MP2)
 * Closed shell explicitly correlated MP2 theory (MP2-R12) and spin-component
   scaled MP2 theory (SCS-MP2)
 * Multireference configuration-interaction (MRCI)
 * Coupled-cluster singles doubles with pertubative triples (CCSD(T))
 * Second/third-order approximate coupled-cluster singles doubles (CC2/CC3)
 * Multireference coupled-cluster singles doubles (MRCCSD)
 * Closed shell and general restricted open shell equation-of-motion coupled-
   cluster singles doubles (EOM-CCSD)

Further features include:

 * Flexible, modular and customizable input format
 * Excited state calculations with the CC2/CC3, EOM-CCSD, CASSCF, MRCI and
   MRCCSD methods
 * Internal coordinate geometry optimizer
 * Harmonic frequencies calculations
 * One-electron properties like dipole/quadrupole moments, natural orbitals,
   electrostatic potential, hyperfine coupling constants or spin density
 * Utilization of molecular point-group symmetry to increase efficiency