Structural and electronic properties of endohedral phosphorus fullerene P@C-60: an off-centre displacement of P inside the cage

Single P-doped endohedral P@ C-60 is investigated via semiempirical and fir st-principles calculations. Unlike the encased N atom, which is situated on the centre of the C60 cage and not covalently bound to the carbon atoms of the fullerene cage, static geometric optimization shows that the encased P atom occupies an off-centre position and is bound to the carbon atoms of t he fullerene cage. The electronic ground state of the doped system is the s pin quarter state, with spin density distribution significantly compressed by the cage.