STRONG DEPENDENCE OF NEGATIVE CLUSTER ION SPECTRA ON PRINCIPAL QUANTUM NUMBER N IN COLLISIONS OF STATE-SELECTED AR-STAR-STAR(ND) RYDBERG ATOMS WITH N2O CLUSTERS

Electron transfer from state-selected Ar**(n d) Rydberg atoms to N2O clusters has been studied over a broad range of principal quantum number (10 ≦n ≦ 45) and at two different Ar velocities (560 and 1000 m/s). A strong n-dependence of the negative cluster ion spectra is detected: while at high n ≳ 30, a rather narrow distribution of (N2O)q·O- and (N2O)q- ions around the major product (N2O)6·O- is found, the distribution widens considerably towards larger q for decreasing n. Correspondingly, the effective rate constants for (N2O)q·O- and (N2O)q- formation show very different n-dependences for low q ≦ 6 and higher q. Possible reasons for the observed behaviour are discussed. © 1990 Springer-Verlag.