Table 3. ALCI Protocol Results with the Optimized Input Parameters for Tetracene, Pentacene, and Hexacene^a.

system	ML algorithm	threshold for CI coeff.	average number of iterations	number of important configurations	number of important SDs	excitation energy (eV)
tetracene (18e, 18o)	KRC	0.01	15.0	1759	53 213	3.86
		0.005	22.7	4788	251 320	3.74
	ANN	0.01	10.3	1491	32 663	3.91
		0.005	18.0	3944	179 952	3.73
	XGBoost	0.01	15.0	1741	53 125	3.88
		0.005	24.3	4642	234 622	3.75
	CASCI (18e, 18o)			44 152 809b	2 363 904 400b	N/A
pentacene (22e, 22o)	KRC	0.01	12.7	1793	31 491	3.50
		0.005	25.0	4780	216 678	3.46
	ANN	0.01	10.7	1713	22 622	3.44
		0.005	16.0	4195	175 336	3.48
	XGBoost	0.01	17.0	1979	47 645	3.47
		0.005	25.0	4941	231 838	3.46
	CASCI (22e, 22o)			3 241 135 527b	497 634 306 624b	N/A
hexacene (26e, 26o)	KRC	0.01	17.3	2430	27 468	2.89
		0.005	18.7	4061	58 237	3.02
	ANN	0.01	12.3	2366	24 760	2.89
		0.005	15.0	4574	101 015	3.03
	XGBoost	0.01	24.0	2670	51 247	2.93
		0.005	36.3	5952	245 534	3.03
	CASCI (26e, 26o)			241 813 226 151b	108 172 480 360 000b	N/A

^aResults are average values of three separate calculations for each model that are performed to obtain better statistics.

^bTotal number of configurations or determinants in the active space.