Semiempirical quantum mechanical PM5 method is employed to investigate the electronic properties of alkali metal dimers. A model molecule of 2C 60 and 2C 60 -X are presented; where X is Be, Mg and Ba respectively. Results indicate that Fullerene dimmer (2C 60 ) has a molecular point group corresponding to D2h. The molecular point group is changed into Cs point group corresponding to 2C 60 -X, which reflects a possible change in the symmetry. Results indicate also that alkali's increases the calculated total dipole moment while both ionization potential and binding energy is slightly decreased. Final heat of formation is increased with temperature; while it increases from 2C 60 to 2C 60 -Mg followed by sharp decrease in case of 2C 60 -Ba. This reflects the thermal stability of the studied Alkali's dimmer as compared with 2C 60 except for 2C 60 -Ba. The calculated ionization potential and binding energy are decrease as the number of alkali atoms (X) increased. As a result of alkali the characteristic bands of C 60 is shifted toward lower wavenumbers with noticeable broadening.

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