Confining C60 in the cages within a zeolite (see Figure) results in th
e modification of the optical properties of the fullerene. This possib
ly results from a weak interaction of the C60 with the wall of the zeo
lite which is, however, strong enough to perturb the electronic struct
ure of the C60 resulting in otherwise forbidden transitions (e.g. whit
e light emission) being observed.