QTAIM functions and QTAIM-DFA parameters for ^AE-∗-^A′E and ^AE-∗-^BE at BCPs of 1-(8-Ph^BEC₁₀H₆)^AE–^A′E(C₁₀H₆^BEMe-8′)-1′ (1–4)^a.

Species (symmetry)	Interaction (X-∗-Y)	ρ b(rc) (eao−3)	c∇2ρb(rc)b (au)	H b(rc) (au)	k b(rc)c	R (au)	θ (°)	ν n (n)d (cm−1)	k f e (mDyn Å−1)	θ p (°)	κ p (au−1)	Classification/characterization
1 (C1)obsdf	(AS-∗-A′S)	0.141	0.004	−0.11	−1.92							r-CS
	(AS-∗-BS)	0.020	0.008	0.00	−1.00							p-CS/r-CS
	(A′S-∗-B′S)	0.021	0.008	0.00	−1.00							p-CS/r-CS
1 (C1)obsdg	(AS-∗-AS)	0.1418	−0.0111	−0.0748	−2.424	0.0757	188.5					SS
	(AS-∗-BS)	0.0229	0.0075	−0.0004	−1.027	0.0075	93.1					r-CS
	(A′S-∗-B′S)	0.0234	0.0076	−0.0005	−1.031	0.0076	93.7					r-CS
1 (C2)calcd	(AS-∗-AS)	0.1373	−0.0097	−0.0697	−2.383	0.0704	187.9	518.7 (48)	1.701	197.5	0.5	SS/Cov-w
	(AS-∗-BS)	0.0227	0.0075	−0.0004	−1.026	0.0075	93.1	181.1 (17)	0.209	117.8	68.9	r-CS/t-HB-wch
2 (C2)calcd	(AS-∗-AS)	0.1356	−0.0089	−0.0677	−2.354	0.0683	187.5	502.9 (48)	1.698	197.5	0.6	SS/Cov-w
	(AS-∗-BSe)	0.0225	0.0068	−0.0006	−1.042	0.0069	95.1	152.0 (16)	0.154	128.1	133.3	r-CS/t-HB-wch
3 (C2)calcd	(ASe-∗-ASe)	0.0970	−0.0018	−0.0403	−2.095	0.0404	182.5	288.9 (28)	0.442	186.6	2.5	SS/Cov-w
	(ASe-∗-BS)	0.0246	0.0070	−0.0011	−1.071	0.0070	93.7	150.9 (15)	0.086	140.1	126.4	r-CS/t-HB-wch
4 (C2)calcd	(ASe-∗-ASe)	0.0948	−0.0013	−0.0387	−2.070	0.0387	181.9	275.5 (28)	0.664	187.1	2.4	SS/Cov-w
	(ASe-∗-BSe)	0.0250	0.0064	−0.0014	−1.098	0.0066	102.3	126.0 (15)	0.105	150.5	141.8	r-CS/CT-MC

^aThe 6-311+G(d) basis set was employed for S and Se with the 6-31G(d,p) basis set for C and H.

^b c∇²ρ_b(r_c) = H_b(r_c) − V_b(r_c)/2, where c = ℏ²/8m.

^c k _b(r_c) = V_b(r_c)/G_b(r_c).

^dCorresponding to the interaction in question. Symmetric and anti-symmetric modes being employed for ^AE-∗-^A′E and ^AE-∗-^BE, respectively.

^eForce constant for ν_n.

^fObserved values for QTAIM parameters.

^gCalculated values for QTAIM parameters evaluated employing the observed structure.

^hTypical HB nature with covalency.