Table 4.

Internal coordinate coefficients^a in the computed eigenvectors and vibrational frequencies(cm⁻¹) of ImH₂(H₂O)₂⁺ and ImD₂(D₂O)₂⁺

νi	Mode	ImH2(H2O)2+				ImD2(D2O)2+
		ν(C4-C5)	ν+(N-C2)	ν+(N-C4,5)	Freq.	ν(C4-C5)	ν+(N-C2)	ν+(N-C4,5)	Freq.
4a	ν(C4-C5)	0.246	−0.170	0.020	1579	−0.355	0.125	0.040	1531
5a	ν+(N-C2)	0.266	0.140	−0.204	1447	0.151	0.275	−0.223	1379
6a	δ+(N-H/D)	−0.067	−0.252	−0.051	1205	0.030	−0.032	0.052	880
7a	ν+(N-C4,5)	−0.043	0.025	−0.321	1121	0.076	0.116	0.270	1135
9a	δ+(C4,5-H)	−0.138	0.069	0.041	1093	0.127	−0.044	−0.110	1095
10a	δ+ring	0.011	0.031	−0.033	929	0.012	−0.093	0.080	927
			ν− (N-C2)	ν− (N-C4,5)			ν− (N-C2)	ν− (N-C4,5)
5b	ν− (N-C2)		0.346	0.079	1525		0.346	0.051	1509
6b	δ− (N-H/D)		0.142	−0.223	1452		0.006	−0.149	941
7b	ν− (N-C4,5)		−0.119	0.203	1315		−0.186	0.324	1356
8b	δ(C2-H)		0.130	−0.101	1178		−0.014	0.034	1252
9b	δ− (C4,5-H)		0.085	0.198	1045		−0.130	0.118	1072
10b	δ−ring		0.017	−0.060	918		−0.005	0.026	896

^aSymmetry coordinate coefficients are given for pairs of bonds related by 2-fold symmetry: ν^±(N-C₂) = (N₁-C₂ +/− N₃-C₂);ν^±(N-C_4,5) = (N₁-C₅ +/− N₃-C₄); δ^± (C_4,5-H) = (C₄-H+/−C₅-H); δ^± (N-H/D)=(C₁-H/D+/−N₃-H/D).