. 2018 Oct 29;9:4502. doi: 10.1038/s41467-018-06615-1

Table 1.

Electronic spectrum of the heme–CO model in the gas phase

State	Energy	Character	Sym.
1⁵MC	0.70	$(d_{yz}, d_{xy}) \to (d_{x^{2} - y^{2}}, d_{z^{2}})$	E
2⁵MC	0.74	$(d_{xz}, d_{xy}) \to (d_{x^{2} - y^{2}}, d_{z^{2}})$	E
1³MC	0.89	$d_{xy} \to d_{x^{2} - y^{2}}$	B₂
3⁵MC	1.40	$(d_{xz}, d_{yz}) \to (d_{x^{2} - y^{2}}, d_{z^{2}})$
2³MC	1.43	$d_{xz} \to d_{z^{2}}$	E
3³MC	1.51	$d_{yz} \to d_{z^{2}}$	E
4³MC	1.62	$d_{xy} \to d_{z^{2}}$	A₂
5³MC	1.86	$d_{yz} \to d_{x^{2} - y^{2}}$	E
6³MC	1.90	$d_{xz} \to d_{x^{2} - y^{2}}$	E
1¹MC	1.90	$d_{xy} \to d_{x^{2} - y^{2}}$	B₂
1³MLCT	2.15	$(a_{1}, d_{yz}, d_{xy}) \to ({e,d}_{x^{2} - y^{2}}, d_{z^{2}})$
2¹MC	2.35	$d_{yz} \to d_{z^{2}}$	E
3¹MC	2.36	$d_{xy} \to d_{z^{2}}$	E
1³Q₁	2.43	a₂ → e	E
⁵MLCT	2.48	$(a_{2}, d_{yz}, d_{xy}) \to ({e,d}_{x^{2} - y^{2}}, d_{z^{2}})$
2³Q₂	2.49	a₂ → e	E
1³MLCT	2.56	$(a_{1}, d_{yz}, d_{xy}) \to (e {,d}_{x^{2} - y^{2}}, d_{z^{2}})$
¹Q_x	2.73	a₂ → e/a₁ → e	E
¹Q_y	2.79	a₂ → e/a₁ → e	E
¹MLCT	2.83	$(a_{2}, d_{yz}) \to ({e,d}_{z^{2}})$

Electronic states up to the bright ¹Q_x,y state are shown. The excitation energies (in eV) are computed at the CASSCF(10,9)/CASPT2/ANO-RCC-VDZP level of theory at the S₀ minimum energy structure obtained at the B3LYP/LANL2DZ level of theory. In addition, the state nature, the character of the dominant transitions and the symmetry label is shown