3.3.3 DFT Results
PECs for FeO were calculated using RODFT with the B3LYP, PBE0, M06, and
M11 functionals (Figs. 16, 17, 18 and 19, respectively). Using B3LYP and the H core
initial guess, a smooth curve is computed for the region between 1.4 and 2.2 Å,
with a ground electronic state of
5 A 1 resulting from the direct product of an A 1
orbital, an A 2 orbital, a B 1 orbital, and a B 2 orbital, all of which are d orbitals on
iron. However, B3LYP calculations are unable to converge to any state after 2.2 Å
(Fig. 16). The Hückel guess produces two electronic states close to equilibrium.
The ground state is a
5
A 1 state that results from single occupation of an A 1 orbital,
an A 2 orbital, a B 1 orbital, and a B 2 orbital, all of which are also iron d orbitals. The
Fig. 14 Points calculated for YO at the CR-CC(2,3) level of theory, using the H core and Hückel
initial guesses
Fig. 15 Points calculated for FeO at the CR-CC(2,3) level of theory, using the H core and Hückel
initial guesses. The point at 2.6 Å using the H core guess and the points at 3.2, 3.4, and 3.5 Å using
the Hückel guess do not converge
22
R. Weber et al.