Table 2. ΔH° of the Anion–Anion Association in kcal/mol^a.

	B3LYP		B3LYP-D3		B2PLYP-D3
	vacuo	ε = 35.7	vacuo	ε = 35.7	vacuo	ε = 35.7	ratio
Ala		1.8		–1.6		–1.1	0.07
Val		1.7		–2.2		–2.1	0.14
Nva		0.7		–3.1		–2.9	0.19
Leu		1.5		–3.5		–3.6	0.24
Ile		2.3		–2.2		–2.4	0.16
Nle		3.4		–2.8		–3.6	0.25
Pro		4.3		0.9		0.5	–0.03
Phe		1.6		–4.3		–4.7b	0.29
Thr	39.7	–1.1	36.8	–5.4	34.7	–5.5	0.38
His	34.3	3.5	28.5	–9.8	28.3b	–10.0b	0.75
Asp	39.6	1.7	37.5	–2.3	37.6	–2.4	0.21
Glu	31.6	–2.5	30.5	–3.9	30.7	–4.4	0.67
Cys	38.0	0.7	35.9	–3.8	36.4	–3.7	0.26

^aAll data have been corrected for ZPE.

^bObtained with 6-31+G**. The last column on the right contains the ratio between the anion–anion B2PLYP/PCM binding energy and the anion–cation one of Table 1.