Description:ORCA is a user-friendly general purpose quantum chemistry software written in C++.
Abstract:ORCA is a user-friendly general purpose quantum chemistry software written in C++. It is suitable for semiempirical methods, HF, DFT, single- and multireference correlated ab initio methods with the inclusion of relativistic effects and solvation. All of its modules have been parallelized. ORCA’s focus are spectroscopic properties of open-shell molecules, but in addition to the determination of molecular properties it offers all the standard types of calculations: single point energies, geometry optimizations, gradients, transition state searches, surface scans, and excited states. ORCA also has a module for molecular dynamics simulations and comes with extensive documentation.