Vacuum UV fluorescence excitation spectroscopy of BCl3 in the range 35–140 nm

Fluorescence excitation spectra of BCl3 have been recorded in the range 35–140 nm (9–35 eV) using synchrotron radiation. Both resonant and non-resonant peaks are observed corresponding to neutral fragment (i.e. BCl2) and parent ion (i.e. BCl+ 3) emission. BCl2 emission results from dissociation of low-lying Rydberg states of BCl3 in the energy range 9–12 eV, and at least two electronic transitions in BCl2 are observed. One (in the range 400–650 nm) originates from dissociation of the 3s and 3p Rydberg states, whilst the other (in the range 250–500 nm) originates from higher members of the s, p and d Rydberg series. The emitting states in BCl+ 3 are the ∼D 2E′ and ∼E 2A′1 states with adiabatic ionization potentials of 15·3 and 17·7 eV. The results are compared with vacuum UV absorption studies of BCl3, and with similar experiments on BF3 which lead to fluorescence processes in BF2 and BF+ 3.