The multiconfiguration Dirac-Fock program grasp has been modified for large-scale, relativistic correlation studies requiring wave-function expansions with several thousand configuration state functions. As a test case, the program was used to study the effects of relativistic correlation on the levels of ${\mathrm{Pr}}^{+3\mathrm{}}$. Our results are in reasonable agreement with experimental data, the lower ${}_{}{}^3{}_{}{}^{}$H and ${}_{}{}^3{}_{}{}^{}$F levels being in good agreement. The previously controversial ${}_{}{}^1{}_{}{}^{}$${\mathit{S}}_0$ term is confirmed by theory for the first time.

• Received 13 September 1991

DOI:https://doi.org/10.1103/PhysRevLett.68.297