title: Assessment of the accuracy of shape-consistent relativistic effective core potentials using multireference spin-orbit configuration interaction singles and doubles calculations of the ground and low-lying excited states of U(4+) and U(5+).
abstract: Multireference spin-orbit configuration interaction calculations were used to determine the accuracy of 60-, 68-, and 78-electron shape-consistent relativistic effective core potentials (RECPs) for uranium V and VI ground and low-lying excited states. Both 5f(n) and (5f6d)(n), (n = 1, 2) reference spaces were investigated using correlation-consistent double-zeta quality basis sets. Accuracy was assessed against gas-phase experimental spectra. The 68-electron RECP calculations yielded low relative and rms errors and predicted the empirical ordering of states most consistently.
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, L-159, Livermore, California 94551, USA.
authors.forename: Eric V
authors.initials: EV
authors.lastname: Beck
authors.forename: Scott R
authors.initials: SR
authors.lastname: Brozell
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Blaudeau
authors.forename: Larry W
authors.initials: LW
authors.lastname: Burggraf
authors.forename: Russell M
authors.initials: RM
authors.lastname: Pitzer