title: Direct experimental probe of the on-site Coulomb repulsion in the doubly charged fullerene anion C70 2-.
abstract: Vibrationally resolved photoelectron spectra were obtained for cold C(70)- and C(70)2-. Accurate values for the first and second electron affinities (EA's) of C(70) were measured as 2.765 +/- 0.010 and 0.002 (+0.01/-0.03)eV, respectively, establishing that C(70)-2 is an electronically stable dianion in the gas phase. The difference between the first and second EA (2.75 eV) provides a direct experimental measure for the on-site Coulomb and exchange interactions between the two excess electrons in C(70)-2. Strong electron correlation effects were also observed between the two excess electrons in C(70)-2.
authors.affiliation: Department of Physics, Washington State University, 2710 University Drive, Richland, WA 99354, USA.
authors.forename: Xue-Bin
authors.initials: XB
authors.lastname: Wang
authors.forename: Hin-Koon
authors.initials: HK
authors.lastname: Woo
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.forename: Manfred M
authors.initials: MM
authors.lastname: Kappes
authors.forename: Lai-Sheng
authors.initials: LS
authors.lastname: Wang