Table 4. Calculated relative energies (kcal mol^–1), geometries (bond lengths in Å, bond angles in degrees), and vibrational frequencies (unscaled, cm^–1) of the NPrO^– anion.

		B3LYP			CCSD(T)			CASPT2
ΔE		0.0	7.6	15.4	0.0	7.0	43.3
OS		Pr(iv)	Pr(iv)	Pr(iii)	Pr(iv)	Pr(iv)	Pr(iii)	Pr(iv)
State		2Φ	2Δ	4H	2Φ	2Δ	4H	2Φ
Electron configuration		fφ1	fδ1	fδ1fφ1σ1	fφ1	fδ1	fδ1fφ1σ1	fφ1
Pr–O		1.933	1.922	1.834	1.951	1.940	1.855	1.950
Pr–N		1.790	1.780	1.794	1.808	1.799	1.826	1.796
∠OPrN		180.0	180.00	180.0	180.0	180.0	180.0	180.0
S 2		0.82	0.94	3.76
ν	Pr–N stretch	813.9	821.8	740.6	767.8	770.2	728.1	813.9
	Pr–O stretch	636.9	610.8	675.6	613.7	609.4	648.7	645.7
	Bend	75.1	85.1	145.6	87.2	96.3	118.4
T 1					0.035	0.034	0.051
D 1					0.094	0.086	0.128