Table 4.

Anharmonic frequencies (in cm⁻¹) and intensities (in km mol⁻¹) for cyc-CHC₃${\text{H}}_2^{+}$ obtained at different levels of theory.

ν	Sym.	B3/SNSD		PW6/julDZ		B2/junTZ		rDSD/junTZ		B2/B3		rDSD/PW6		rDSD/B3		TZ/aVTZa
		ν	I	ν	I	ν	I	ν	I	ν	I	ν	I	ν	I	ν
ν1	a1	3,242	89.15	3,256	213.92	3,261	188.89	3,252	159.06	3,262	188.96	3,243	217.46	3,254	202.75	3237.1
ν2	a1	3,173	47.80	3,204	25.91	3,195	32.81	3,195	43.11	3,194	27.39	3,181	17.69	3,193	27.27	3182.2
ν3	a1	1,948	32.75	1,977	43.62	1,975	58.99	1,984	77.84	1,973	66.32	1,984	43.62	1,987	33.98	1947.8
ν4	a1	1,647	45.54	1,664	41.55	1,666	33.30	1,665	57.64	1,672	41.27	1,671	45.65	1,673	47.57	1641.9
ν5	a1	903	3.50	897	5.08	902	0.81	902	3.55	901	1.92	873	0.31	895	1.50	884.4
ν6	a1	761	22.08	804	25.51	744	6.46	766	14.54	751	22.70	719	5.33	746	14.77	760.2
ν7	a2	743	0.00	738	0.00	736	0.00	723	0.00	735	0.00	723	0.00	720	0	713
ν8	b1	717	67.04	713	66.81	722	68.65	719	68.28	723	67.48	720	67.62	719	67.62	729
ν9	b1	410	65.38	481	96.72	496	90.31	511	87.86	473	100.36	515	92.55	487	95.23	480.8
ν10	b1	315	35.31	303	8.67	380	4.26	372	5.64	343	0.08	388	12.01	336	13.79	154.3
ν11	b2	3,117	192.57	3,146	199.69	3,141	207.44	3,140	205.27	3,141	206.76	3,129	200.04	3,138	193.33	3130.1
ν12	b2	964	5.79	962	7.78	974	8.12	968	7.34	970	8.83	966	8.11	965	9.21	970.1
ν13	b2	909	0.02	903	0.03	901	0.91	921	0.48	896	1.23	907	0.03	908	0.02	894
ν14	b2	594	25.65	653	30.44	531	21.92	539	22.88	525	22.11	530	29.72	532	25.18	547.4
ν15	b2	199	23.79	189	22.13	172	26.35	163	26.95	172	26.33	160	22.46	162	23.91	175.9

^aTaken from Westbook et al. (2020).