. 2016 Mar 10;144(10):104304. doi: 10.1063/1.4942019

TABLE XIV.

Energy differences for the 1¹A₁ state, in mh, relative to the energy of this state at its open minimum (OM).

		Active space of the reference wave function
		CAS(2,2)*	CAS(2,2)	CAS(6,4)*	CAS(6,4)	CAS(12,7)*^a	CAS(18,10)	CAS(12,9)*	CAS(18,12)
Geometry		Excluding 2s excitations	Including 2s excitations	Excluding 2s excitations	Including 2s excitations	Including 2s excitations	Including 2s excitations	Excluding 2s excitations	Including 2s excitations
ΔTS	Ref.	80.30	80.30	63.78	63.78	66.09	65.99	84.09	84.10
	Ref. + SD	93.92	100.48	74.84	79.56	78.92	86.69	93.91	88.42
	Ref. + SDT	94.46	101.17	85.05		86.96		94.40
	Ref. + SDTQ^b	86.99	92.89	79.62		80.79
		(86.60)^b
ΔXM	Ref.	80.61	80.61	63.81	63.81	66.12	66.03	83.41	83.81
	Ref. + SD	94.19	100.76	75.05	79.73	79.12	86.90	93.44	88.07
	Ref. + SDT	94.58	101.34	85.25		86.58		93.90
	Ref. + SDTQ^b	86.72	92.30	79.32		81.24
ΔCI	Ref.	105.80	105.80	80.08	80.08	82.43	82.48	86.56	87.35
	Ref. + SD	111.99	122.80	84.43	92.45	88.49	100.13	101.43	94.63
	Ref. + SDT	106.74	118.15	93.82		95.15		102.08
	Ref. + SDTQ^b	93.97	103.08	86.36		85.38
		(93.55)^b
ΔRM	Ref.	1.22	1.22	61.72	61.72	61.76	61.24	50.62	47.59
	Ref. + SD	30.35	30.70	39.23	48.83	42.11	74.02	53.71	47.61
	Ref. + SDT	42.43	42.91	42.76		43.89		54.03
	Ref. + SDTQ^b	44.59	45.05	37.67		37.76

^{^a}

Energies for the CAS(12,7)* calculations were determined using the CASSCF(6,4) optimized orbitals (see the end of Section VI A).

^{^b}

The SDTQ values without parentheses were obtained using the CEEIS extrapolation for the CISDTQ increments. The values in parentheses for CAS(2,2)* were obtained by exact CISDTQ calculations.