Structures and Stabilities of Alkaline Earth Metal Oxide Nanoclusters: A DFT Study

Table 3

Binding energies, Fermi energies, and HOMO-LUMO gaps (in eV) for (MO)₅ clusters.

M	Structure	Binding energy		HOMO-LUMO gap		Fermi energy
		LDA (PWC)	GGA (PW91)	LDA	GGA	LDA	GGA
Mg	Ladder	−41.65	−37.62	2.20	2.18	−3.59	−3.34
	Hexagonal	−41.65	−37.62	2.21	2.20	−3.58	−3.34
	MgO-I	−41.52	−37.57	2.25	2.19	−3.59	−3.34
	Decagonal	−41.08	−37.41	3.36	3.30	−3.79	−3.47
	Chair	−42.87	−38.57	2.30	2.24	−3.54	−3.28
	MgO-II	−41.52	−37.57	2.24	2.17	−3.59	−3.34
Ca	Ladder	−45.53	−41.19	1.91	1.82	−1.92	−1.70
	Hexagonal	−45.53	−41.19	1.92	1.84	−1.93	−1.71
	CaO-I	−45.11	−40.88	1.87	1.75	−1.91	−1.70
	Decagonal	−43.19	−39.37	1.99	1.92	−1.52	−1.35
	Chair	−47.74	−43.01	2.00	1.90	−2.16	−1.90
	CaO-II	−45.05	−40.88	1.41	1.76	−1.86	−1.70
Sr	Ladder	−44.92	−42.81	1.91	1.89	−1.81	−1.63
	Hexagonal	−43.60	−41.83	1.01	1.05	−1.84	−1.63
	SrO-I	−44.68	−40.47	1.65	1.56	−1.81	−1.66
	Decagonal	−42.50	−38.81	1.94	1.71	−1.51	−1.37
	SrO-II	−44.68	−40.60	1.64	1.46	−1.81	−1.67
Ba	Ladder	−46.54	−47.44	1.97	2.14	−1.64	−1.52
	Hexagonal	—	−46.95	—	1.77	—	−1.53
	BaO-I	−46.42	−42.37	1.98	1.82	−1.69	−1.57
	Decagonal	—	−43.07	—	1.86	—	—
	BaO-II	−46.41	−42.35	1.95	1.80	−1.68	−1.56