The second spectrum of silicon

Abstract

New observations of the spectrum Si II from λ 700 to λ 9500 are described, 300 lines being listed in addition to those previously assigned to this spectrum. The analysis includes details of the perturbations of the 3 s 2 nx 2 X series up to x = g . Structures of type 3 s 3 p ( 3 P ) nx up to x = f have been identified and many peculiarities found. A large proportion of the levels show auto-ionization effects, even up to a term at 25000 cm -1 above ionization. The same term also shows an anomalous degree of excitation in the hollow cathode for two levels which cannot auto-ionize.