Emissionspectroscopic Investigation of Bci3 Discharges

Radiofrequency discharges in neat BCI3 exhibit 3 broad molecular emissions with intensity maxima at about 305, 350, and 480 nm. The 350 nm system consists of a progression of bands with an average separation of about 130 cm−1. All three emissions have an identical excitation kinetics in pulse discharges and are, therefore, believed to originate from the same emitter. Arguments are given that the emitter might be electronically excited BCl2. The dominant process of BCl(A) formation in neat BCl3 at low r.f. power is shown to be direct electron impact excitation of BCl(X). A transient excess population of BCl(A1II) in BCl3/Ar discharges is explained as due to an energy transfer from argon metastables.