Table 4. Symmetry-Adapted Perturbation Theory-Based Energy Decomposition Analysis (SAPT-EDA) for HX···XH, C₆H₅X···XC₆H₅, and CH₃X···XCH₃ (Where X = F, Cl, Br, and I) Complexes Calculated (in kcal/mol) at the MP2/aug-cc-pVTZ(PP) Level of Theory and the Most Favorable X···X/X′ Distances.

complexes		interaction type	Eelst(10)	Eexch(10)	Edisp	Eind	ESAPT0a	ΔΔEb
hydrogen halide	HI···IH	σ-hole···σ-hole	0.66	1.02	–1.91	–0.29	–0.52	–0.09
	HI···BrH	di-σ-hole	0.44	0.86	–1.62	–0.20	–0.53	–0.05
	HI···ClH	di-σ-hole	0.16	0.80	–1.41	–0.15	–0.61	0.00
	HI···FH	halogen bond	–1.32	1.22	–1.10	–0.31	–1.50	0.36
	HBr···BrH	σ-hole···σ-hole	0.33	0.72	–1.40	–0.14	–0.48	–0.03
	HBr···ClH	di-σ-hole	0.18	0.62	–1.18	–0.10	–0.48	–0.01
	HBr···FH	halogen bond	–0.70	0.86	–0.90	–0.20	–0.94	0.20
	HCl···ClH	σ-hole···σ-hole	0.15	0.54	–1.02	–0.07	–0.39	0.00
	HCl···FH	halogen bond	–0.15	0.53	–0.67	–0.11	–0.41	0.08
	HF···FH	repulsive	c	c	c	c	c	c
halobenzene	C6H5I···IC6H5	σ-hole···σ-hole	0.40	1.92	–2.98	–0.47	–1.12	–0.11
	C6H5I···BrC6H5	di-σ-hole	0.25	1.66	–2.64	–0.35	–1.08	–0.05
	C6H5I···ClC6H5	di-σ-hole	0.03	1.46	–2.30	–0.28	–1.08	0.01
	C6H5I···FC6H5	halogen bond	–0.99	1.51	–1.80	–0.33	–1.62	0.36
	C6H5Br···BrC6H5	σ-hole···σ-hole	0.21	1.39	–2.31	–0.25	–0.96	–0.04
	C6H5Br···ClC6H5	di-σ-hole	0.11	1.25	–2.05	-0.20	–0.89	–0.01
	C6H5Br···FC6H5	halogen bond	–0.46	1.12	–1.53	–0.22	–1.09	0.16
	C6H5Cl···ClC6H5	σ-hole···σ-hole	0.13	1.03	–1.76	–0.15	–0.75	0.00
	C6H5Cl···FC6H5	halogen bond	–0.04	0.77	–1.24	–0.15	–0.65	0.05
	C6H5F···FC6H5	repulsive	c	c	c	c	c	c
halomethane	CH3I···ICH3	σ-hole···σ-hole	0.25	1.82	–2.69	–0.39	–1.02	–0.05
	CH3I···BrCH3	di-σ-hole	0.18	1.57	–2.36	–0.31	–0.91	–0.03
	CH3I···ClCH3	di-σ-hole	0.01	1.43	–2.04	–0.26	–0.85	–0.01
	CH3I···FCH3	halogen bond	–0.92	1.57	–1.48	–0.41	–1.24	0.23
	CH3Br···BrCH3	σ-hole···σ-hole	0.24	1.31	–2.04	–0.22	–0.70	–0.06
	CH3Br···ClCH3	di-σ-hole	0.22	1.14	–1.74	–0.18	–0.56	–0.05
	CH3Br···FCH3	halogen bond	–0.14	1.05	–1.19	–0.27	–0.54	0.03
	CH3Cl···ClCH3	σ-hole···σ-hole	0.34	0.87	–1.41	–0.13	–0.33	–0.06
	CH3Cl···FCH3	halogen bond	0.44	0.59	–0.86	–0.17	0.01	–0.07
	CH3F···FCH3	repulsive	c	c	c	c	c	c

^aE_SAPT0 = E_elst⁽¹⁰⁾ + E_exch + E_disp + E_ind.

^bΔΔE = E_{MP2/aug-cc-pVTZ(PP)} – E_SAPT0.

^cNo SAPT-EDA was performed since no local minimum was observed in the corresponding potential energy surface (PES) curves for A–F···F–A complexes (Figure 4).