Table 2. Comparison of PBEsol and PBEsol+U Level Lattice Constants (a = b ≠ c and α = β = γ), Cell Volume (V), and Mass Density (ρ) of A-TiO₂ with Experiment^a,^b.

PAW	PBEsol					PBEsol+U
	a/Å	b/Å	c/Å	V/Å3	ρ/gcm–3	a/Å	b/Å	c/Å	V/Å3	ρ/gcm–3
Ti_std	3.800	3.800	9.547	137.85	3.85	3.858	3.858	9.553	142.19	3.73
Ti_pv	3.777	3.777	9.575	136.59	3.88	3.827	3.827	9.591	140.47	3.78
Ti_sv	3.773	3.773	9.564	136.14	3.90	3.817	3.817	9.575	139.49	3.80
expt.68	3.784	3.784	9.518	136.28	3.89	3.784	3.784	9.518	136.28	3.89

^aα = β = γ = 90° for the theoretical methods applied.

^bThree different PAW potentials used.