This approach was tested on 49 isolated fragment pairs extracted from a seven-nucleobase-long DNA duplex in water (see Fig. ). The results show that correlates very well with (R 2 = 0.988). Hence, the net effect of the implicit solvent is to modulate intermolecular interactions, decreasing their absolute value to an extent that is proportional to their strength. A fragmentpairwise decomposition of the overall into fragment-pairwise terms can thus be obtained as: