Table 5:

ph-AFQMC adiabatic ionization energies at the complete basis set limit as a function of metallocene and methodology. The mean absolute errors (MAE), maximum errors (MaxE), root-mean-square deviations (RMSD), and the mean signed errors (MSE) are included. All units are in kcal/mol. (1) = B3LYP reorganization energy and (2) = AFQMC PC/CAS reorganization energy. All units are in kcal/mol.

	ETE Expt	AFQMC PC UHF Trial	AFQMC PC CAS Trial	AFQMC CS (1) CAS Trial	AFQMC CS (2) CAS Trial
V(Cp)2	154.5 ± 1.5	157.64 ± 1.55	160.25 ± 2.15	155.44 ± 1.61	153.7 ± 1.52
Cr(Cp)2	127.5 ± 1.5	127.04 ± 1.43	133.54 ± 1.96	127.63 ± 1.81	131.18 ± 2
Mn(Cp)2	142.5 ± 1.5	156.26 ± 1.54	151.69 ± 2	158.53 ± 1.97	146.09 ± 2.37
Fe(Cp)2	153.1 ± 1.5	158.41 ± 1.84	158.37 ± 2.32	150.34 ± 1.75	152.78 ± 2.02
Co(Cp)2	123.5 ± 1.5	119.06 ± 1.6	122.18 ± 1.85	128.1 ± 1.52	124.35 ± 1.83
Ni(Cp)2	143.8 ± 1.5	144.75 ± 1.42	143.49 ± 1.64	148.25 ± 1.7	144.25 ± 2.15
MAE		4.68 ± 0.89	4.65 ± 1.02	4.82 ± 0.93	1.61 ± 1.02
∣MaxE∣		13.76 ± 2.15	9.19 ± 2.5	16.03 ± 2.47	3.68 ± 2.5
RMSD		6.43	5.53	7.15	2.16
MSE		3.04 ± 0.89	4.1 ± 1.02	3.9 ± 0.93	1.24 ± 1.02