Absolute cross sections for excitation of the 2s S-2 -> 2p P-2 transition in B2+ and for electron-impact single ionization of B2+

Absolute cross sections for electron-impact excitation of the 2s S-2-->2p P -2 transition of B2+ measured between 5.4 and 7.0 eV are presented. The res ults are in good agreement with the R-matrix-with-pseudostates (RMPS) calcu lation of Marchalant et al. [J. Phys. B 30, L435 (1997)]. Also presented ar e cross sections for electron-impact single ionization of B2+, including me asurements between 25 and 200 eV and calculations using the RMPS and time-d ependent close-coupling methods. The measured ionization cross sections are about 14% higher near the peak than previous measurements by Crandall er n l. [Phys. Rev. A 34, 1757 (1986)], but agree well with experimental data of Hofmann et al. [Z. Phys. D 16, 113 (1990)] and with the present and other theoretical predictions. [S1050-2947(98)01212-8].