AB-INITIO STUDY OF CHEMICAL-SPECIES IN THE BCL3 PLASMA - STRUCTURE, SPECTRA, AND DECOMPOSITION PATHS

Industrially important plasmas offer a variety of complicated molecula r processes that benefit from predictive quantum chemical techniques. Ab initio coupled-cluster and MBPT methods are used to characterize st ructures, vibrational frequencies, ionization potentials, electron aff inities, and excited states for the main fragments in the BCl3 plasma, i.e. BCl3, BCl2, BCl, and their anions and cations for which few expe rimental results exist. The excited, electron attached, and ionized st ates are calculated by employing the equation-of-motion coupled cluste r (EOM-CC) method. Recent results from a photofragmentation study and an electron collision experiment are analysed based on the calculated results. Some features of the potential energy surfaces of excited sta tes of BCl2 are discussed in order to explain the origin of the experi mental fluorescence spectrum. We also consider possible microscopic pr ocesses with low energy, such as the formation and destruction of neut ral and ionic species, decomposition paths, and the role of each fragm ent. While decomposition through transient states of BCl3- by electron attachment is the most probable path for low-energy electron attachme nt, decomposition through excited states of BCl3 can play a role only when there is no other way to make the BCl3+ ion. (C) 1997 American In stitute of Physics.