Table 1.

CS. Ionisation energies I.E. (in eV) and pole strengths $R_I$ obtained at the MS-CASPT2 and EOM-CCSD levels with the aug-cc-pVTZ basis set. ${}^{†}$ The state characterization is based on the CI configurations with weight higher than 0.1. KT I.E. are the Koopmans theorem Hartree-Fock molecular orbital energies. Experimental values from Ref. [30].

Ionic State (I)	MS-CASPT2 State Character ${}^{†}$	Exp.	KT	MS-CASPT2		EOM-CCSD a
		I.E.	I.E.	I.E.	${\mathit{R}}_{\mathit{I}}$	I.E.	${\mathit{R}}_{\mathit{I}}$
7$\sigma$	7${\sigma }^1$(0.79)	11.33	12.81	11.03	0.8354	11.52	0.8672
2$\pi$	2${\pi }^3$(0.87)	12.79	12.58	12.81	0.9019	13.06	0.9091
Satellite A	7${\sigma }^1$2${\pi }^3$3${\pi }^1$(0.50) + 6${\sigma }^1$(0.28)	16.05		15.73	0.3242	20.32	0.1056
6$\sigma$	6${\sigma }^1$(0.47) + 7${\sigma }^1$2${\pi }^3$3${\pi }^1$(0.24)	18.00	18.85	17.75	0.4915	17.26	0.7683
Satellite B	5${\sigma }^1$(0.17) + 6${\sigma }^1$2${\pi }^3$3${\pi }^1$(0.22)			22.85	0.1810	24.83 b	0.468

^a Some EOM-CCSD (and EOM-CC3) results can also be found in Ref. [23]. ^b Main composition according to EOM-CCSD: $5{\sigma }^1+7{\sigma }^1$ + 7${\sigma }^1$2${\pi }^3$3${\pi }^1$ + 6${\sigma }^1$2${\pi }^3$3${\pi }^1$.