On the Relevance of Considering the Intermolecular Interactions on the Prediction of the Vibrational Spectra of Isopropylamine

Table 3

Comparison of the B97D CP-corrected frequency shifts predicted by the PiMM and the full cluster approaches for the NH₂ and C(2)–H related vibrational modes. Only the vibrational shifts for the O3a and O4a clusters are presented (for the other iPram clusters see Table S8 of the Supplementary Material).

Mode^a	O3a		O4a
	PiMM	Full^b	PiMM	Full^b
𝜈 asNH2	−38	−36	−79	−115
𝜈 sNH2	−85	−130	−172	−112
𝛿NH2	29	36	62	53
tNH2	21	26	42	44
𝜔NH2	73	71	130	76
𝜏NH2	158	219	297	314
𝜈 C(2)–H	4	−3	−12	−16
𝛽C(2)–H	1	3	1	4
𝛾C(2)–H	5	3	8	3

^a𝜈 = stretching, 𝛿 = deformation, t = twisting, 𝜔 = wagging, 𝜏 = torsion, 𝛽 = in-plane deformation and 𝛾 = out-of-plane deformation.
bFull-cluster approach.