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

TABLE VI.

Number of determinants generated for the reference, CISD, CISDT, and CISDTQ active spaces of A₁ symmetry, using different reference active spaces for ozone. The meaning of the italic and bold fonts is discussed in the text at the beginning of Section IV C. The parentheses (x) imply (× 10^x).^a

	Excitation level
			Ref. + SDT			Ref. + SDTQ
Reference active space	Ref.	Ref. + SD	m = 30	m = 40	m = M^b	m = 30	m = 40	m = M^b
Number of determinants generated when 2s excitations are included
CAS(18,12)	1.2 (4)	5.9 (8)	2.5 (9)	6.2 (9)	4.8 (10)	4.8 (10)	1.6 (11)	>2.5 (12) ^c
CAS(18,10)	3.0 (1)	4.8 (6)	4.0 (7)	9.6 (7)	6.9 (8)	1.3 (9)	4.3 (9)	>6.0 (10) ^c
CAS(6,4)	4.0 (0)	2.5 (6)	2.8 (7)	6.6 (7)	4.8 (8)	1.1 (9)	3.5 (9)	>5.0 (10) ^c
CAS(2,2)	2.0 (0)	8.0 (5)	1.0 (7)	2.5 (7)	1.8 (8)	4.7 (8)	1.5 (9)	2.1 (10)
Number of determinants generated when 2s excitations are excluded
CAS(12,9)*	1.8 (3)	3.7 (7)	1.0 (8)	2.5 (8)	1.9 (9)	1.2 (9)	4.0 (9)	6.1 (10)
CAS(12,7)*	1.3 (1)	1.0 (6)	5.5 (6)	1.3 (7)	9.3 (7)	1.1 (8)	3.5 (8)	4.9 (9)
CAS(6,4)*	4.0 (0)	8.4 (5)	5.1 (6)	1.2 (7)	8.7 (7)	1.1 (8)	3.5 (8)	4.8 (9)
CAS(2,2)*	2.0 (0)	3.2 (5)	2.5 (6)	6.0 (6)	4.3 (7)	6.7 (7)	2.1 (8)	2.9 (9)

^{^a}

The exact values are listed in Table T2 of the supplementary material.⁴¹

^{^b}

M = 77 for CAS(18,10), CAS(6,4), CAS(2,2), CAS(12,7)*, CAS(6,4)*, and CAS(2,2)* active spaces, the value of M = 75 for CAS(18,12) and CAS(12,9)*. See text in Section IV B.

^{^c}

Estimated values.