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

Table 2

Binding energies, HOMO-LUMO gaps, and Fermi energies (in eV) for (MO)₄ clusters.

M	Structure	Binding energy			HOMO-LUMO gap		Fermi energy
		LDA (PWC)	GGA (PW91)	B3LYP/6-311G(d)^a	LDA	GGA	LDA	GGA
Mg	Slab	−33.87	−30.38	−27.04	2.70	2.65	−3.45	−3.22
	Octagonal	−32.41	−29.47	−26.12	3.22	3.14	−3.79	−3.51
	Ladder	−32.18	−29.03	−25.63	2.09	2.08	−3.60	−3.35
Ca	Slab	−38.50	−34.63	−32.37	3.14	2.89	−2.00	−1.81
	Octagonal	−34.91	−31.70	−29.56	1.15	1.35	−1.86	−1.75
	Ladder	−35.58	−32.17	−28.79	1.88	1.78	−1.95	−1.74
Sr	Slab	−37.70	−34.67	—	3.32	2.96	−2.02	−1.82
	Octagonal	−34.87	−31.69	—	1.33	1.17	−1.82	−1.69
	Ladder	−35.30	−33.69	—	1.96	1.92	−1.87	−1.69
Ba	Slab	−39.83	−36.15	—	3.65	3.38	−2.01	−1.78
	Octagonal	−36.48	−33.31	—	1.67	1.48	−1.72	−1.61
	Ladder	−36.77	−33.57	—	2.09	2.24	−1.73	−1.60

aFrom reference [40, 41].