Abstract: The molecular geometry and electronic structure of fullerene C₃₆ isomers with C_2v, D_2d, D_3h and D_6h symmetries and hydrofullerenes C₃₆H_2n of D_2d, D_3h and D_6h isomers with different quantum states are studied at the 3-21Glevel of the theory using density functional B3LYPand ab initio HFmethods. The results of calculations show that the effect of electronic correlation have an important influence. Their most stable structures are D_6h isomer with a quantum stae ³A_2u among C₃₆ and hydrofullerene C₃₆H₁₂ of D_3h isomer with a quantum state ¹A^1' adding hydrogen at C₂ position among C₃₆H_2n.

Key words: Fllerene C₃₆, C₃₆H_2n, HF, B3LYP, 3-21G