Strongly Bound Frenkel Excitons on TiO₂ Nanoparticles: An Evolutionary and DFT Approach

Table 2

Parameters calculated with the PBE/PAW method for the Wannier exciton model of anatase and rutile using the high-frequency () and static dielectric constants ().

Phase	Method	^a			(meV)^a			a x; (Å)
		Anatase		0.51	0.48	0.44	242.6			13.77	5.81	38.7	10
PBE	0.41		0.35	0.36	137.6	1.99	4.73	47.6	13
PBEsol	0.37		0.32	0.32	125.7	2.57	4.28	52.5	14
Experimental							180^b
Rutile		0.91	0.91	1.16	313.8	8.10	0.55	77.3	26
	PBE	0.85	0.76	1.07	187.1	121.6	0.51	83.4	28
	PBEsol	0.78	1.0	1.00	169.5	0.06	0.47	89.6	30
	Experimental						4^c

^aReduced effective mass () and calculated using different dielectric constants. ^bExciton binding energy for direct transition from Ref. [13]. ^cFrom Ref. [11].