Table 3.

Comparison of surface structure parameters for the (100) surface goethite + water between PBE96 AIMD and PBE96 + Grimme2 AIMD simulations of Fe₂₄O₆₀H₄₈ + 53 H₂O and fitted structure from CTR experiments of Ghose et al. [22]

Surface structure parameters	PBE96 AIMD	PBE96 + Grimme2 AIMD	Exp. CTR model
R(Fe–OII)	~2.40	~2.34	2.152
σ(Fe–OII)
R(Fe–OI)	2.10	2.11	2.097
σ(Fe–OI)	0.08	0.08
R(Fe–Oi)	2.02	2.00	1.950
σ(Fe–Oi)	0.07	0.08
R(Fe–Oii)	1.94	1.97	1.966
σ(Fe–Oii)	0.06	0.07
∠OI–Fe–OII	80.2	81.1	81.25
σ ∠OI–Fe–OII	5.5	5.3
∠OII–Fe–Oi	87.7	87.7	82.85
σ ∠OII–Fe–Oi	5.8	5.7
∠OII–Fe–Oii	170.4	170.3	178.89
σ ∠OII–Fe–Oii	4.9	5.0
∠OI–Fe–Oi	81.8	82.6	80.85
σ ∠OI–Fe–Oi	3.6	3.4
∠OI–Fe–Oii	97.1	94.5	99.5
σ ∠OI–Fe–Oii	5.7	4.7
∠OIII–Fe–Oii	97.6	97.1	96.5
σ ∠OIII–Fe–Oii	4.8	4.3

See Fig. 4c for definitions of OI, OII, Oi, and Oii oxygens (length unit: Å, angle unit: °)