Table 1 .

DFT OLYP-D3-BJ Calculated Geometric and Mulliken Net Spin Properties of the Active Site of OxyMb (Figure 2).^a

	Geometry (Å, degree)						ΔEBS b	Net Spin c
	Fe-N(H93)	Fe-O1	O1-O2	∠FeO1O2	O2⋯Nε(H64)	O2⋯O341		Fe	O1	O2
	Hlink-Fixed d	2.01	1.79	1.32	117.7	2.85		2.85	0.0	0.71	−0.32	−0.40
Full-Opt. e	2.02	1.80	1.32	117.3	2.87	2.84	−1.1	0.73	−0.33	−0.41
Exp.	2.07	1.83	1.21	115.6	2.77	1.47

^a.The initial geometry of the oxymyoglobin (oxyMb) active site model cluster is taken from the X-ray crystal structure 1MBO,³¹ which is also given here as the experimental (Exp.) data for comparison.

^b.Relative calculated broken-symmetry state energies in kcal mol⁻¹.

^c.The Mulliken net spin populations (number of unpaired electrons) on Fe, O1, and O2.

^d.During geometry optimization, the positions of the H_link atoms (replacing the C_α atoms) on His93 and His64 side chains are fixed.

^e.The geometry of the model cluster is fully optimized without constraint.