Table 3. HOMO–LUMO Energy Difference or Gap (Δ, eV) of CaC₁₂ and CaC₁₂–7H₂.

	single bond			triple bond			center
system	HOMO (eV)	LUMO (eV)	Δ	HOMO (eV)	LUMO (eV)	Δ	HOMO (eV)	LUMO (eV)	Δ
CaC12	–4.292	–3.332	0.960	–4.295	–3.33	0.965	–5.206	–4.601	0.605
CaC12–H2	–4.222	–3.290	0.932	–4.238	–3.301	0.937	–5.240	–4.782	0.458
CaC12–2H2	–4.137	–3.211	0.926	–4.196	–3.271	0.925	–5.240	–5.103	0.137
CaC12–3H2	–4.211	–3.261	0.950	–4.182	–3.233	0.949	–5.272	–5.061	0.211
CaC12–4H2	–4.201	–3.251	0.950	–4.215	–3.261	0.954	–5.275	–5.079	0.195
CaC12–5H2	–4.207	–3.273	0.934	–4.224	–3.283	0.941	–5.246	–5.050	0.196
CaC12–6H2	–4.233	–3.292	0.941	–4.232	–3.297	0.935	–5.181	–5.013	0.168
CaC12–7H2	–4.223	–3.281	0.942	–4.241	–3.301	0.940	–5.194	–5.025	0.169