Table III.

Coordinates of 5-atom structures for use in the Bethe-Salpeter equations to compute near-edge spectra of cubic or tetragonal simple ATiO₃ perovskites, given root-mean-square fluctuations associated with the ti_u local coordinate (Table I). The origin is chosen such that the crystallographic average position of one O atom is (0.5, 0.5, 0.0). A_z and O_z coordinates are set at their average values.

		T=300 K:
Ion	x	y	z
A	0	0	Az
Ti	$0.5+(2/\sqrt{6})\sigma (t_{1u}^{(1)}(x))$	$0.5+(2/\sqrt{6})\sigma (t_{1u}^{(1)}(y))$ 0.5	$0.5+(2/\sqrt{6})\sigma (t_{1u}^{(1)}(z))$Oz
O	$0.0-(1/\sqrt{6})\sigma (t_{1u}^{(1)}(x))$	0.5	Oz
O	0.5	$0.0-(1/\sqrt{6})\sigma (t_{1u}^{(1)}(y))$	Oz
O	0.5	0.5	$0.0-(1/\sqrt{6})\sigma (t_{1u}^{(1)}(z))$