HIGH-RESOLUTION LASER SPECTROSCOPY BEYOND 18 EV - THE B-2-SIGMA(-X-1-SIGMA(+)(G) PHOTOELECTRONIC TRANSITION OF N-2()(U)[)

Coherent, narrow-bandwidth laser radiation has been generated beyond 1 8 eV. The radiation has been used to record a rotationally resolved pu lsed-field-ionization zero-kinetic-energy photoelectron spectrum of th e B (2) Sigma(u)(+) <-- X (1) Sigma(g)(+) transition of N-2. Analysis of the rotational structure indicates that the removal of one of the t wo 2 sigma(u) inner-valence-shell electrons is accompanied by substan tial changes in the core rotational angular momentum quantum number: R otational branches are observed with Delta N = N+ - N = +/- 1 and +/- 3, where N+ and N represent the core rotational angular momentum of th e ion and the neutral, respectively. These branches can be explained b y the ejection of a photoelectron with dominant iota = 0 and iota = 2 character. (C) 1998 Elsevier Science B.V.