Table 3.

Energies (−E in kcal mol⁻¹) obtained from semi-empirical calculations (CC = Counterpoise Correction)

Basis set level/ Base pair	MP2	MP2
	6-31G*	6-31+G**	MP2	MP2
			6-31G*	6-31+G**
			(CC)	(CC)
Point energy calculation based on crystallographic data
F104:G209	8.3	6.9	4.4	4.8
F204:G109	9.2	7.7	5.1	5.6
F304:G409	7.2	6.4	4.2	4.7
F404:G309	8.4	7.1	4.7	5.1
F4:A21	5.4	4.9	2.6	2.8
F16: A9	5.6	4.9	2.6	2.9
average F:G	8.3	7	4.6	5.1
average F:A	5.5	4.9	2.6	2.9
Energy calculation from base–pair geometry optimization
T:A	18.2	16.5	12.3	12.7
F:A	7.6	7.2	4	4.3
T:G	19.6	19.3	14.1	15.5
F:G	11.5	8.4	6.4	7