ORCA
ORCA is an ab initio, DFT, and semi-empirical SCF-MO package developed by Frank Neese et al. at the Max Planck Institut für Kohlenforschung.
Orbital and density plots
If you run a calculation using !LARGEPRINT on the main input and Save output to a file, you can visualize the orbitals by opening the basename.out file in Avogadro.
Useful references:
ORCA input library
ORCA Tutorials by FAccTs
Citation
Published works based on the usage of ORCA must contain appropriate citation. The generic reference for ORCA are:
Neese, F. (2012) The ORCA program system, Wiley Interdiscip. Rev.: Comput. Mol. Sci., 2, 73-78.
Neese, F. (2017) Software update: the ORCA program system, version 4.0, Wiley Interdiscip. Rev.: Comput. Mol. Sci., 8, e1327.