Strong alignment effect in quasiresonant charge transfer between laser-excited sodium atoms and C-60

We observe a strong alignment effect ([rho(sigma sigma)] = 0.8 +/- 0.2) in quasiresonant charge transfer collisions between Na(3p) and C-60 at thermal energies. This implies that practically only excited sodium atoms with the ir electronic charge cloud asymptotically aligned along the relative veloci ty vector lead to charge transfer. This is interpreted as being due to a co mbination of "orbital locking" and the strong rr-like character of the full erene lowest unoccupied molecular orbital. [S0031-9007(99)08901-2].