Abstract
Geometry and energy of formation of single molecules: fullerene C60, CS2 and tetrathiofulvalene (TTF) and their complexes: C60 +CS2 and C60 +TTF were obtained using Hartree-Fock (HF) and Density Functional Theory methods in various basis sets. Weak chemical interactions were estimated enough well using HF/6-31G for a comparison of various geometrical conformations of these complexes. Energy of formation evaluation in charge-transfer complex C60 +TTF is performing additionally calculating complex with far-separated molecules.