Studies of collisions between C60 and K(np) Rydberg atoms with 35 ≤ n ≤ 125 indicate that C60 can attach very-low-energy electrons to form long-lived C60- ions. The rate constant for negative ion formation is observed to be small, ≈ 10-8 cm3 s-1, and to be independent of n pointing to s-wave capture. Possible mechanisms for this are discussed, including the formation of image-charge-bound C60- ions. © 1995.
