PHOTOIONIZATION MASS-SPECTROMETRIC STUDY OF FRAGMENTATION OF SIBR4 AND GEBR4 IN THE RANGE 400-1220-A - CREASEY, JC; LAMBERT, IR; TUCKETT, RP; CODLING, K; FRASINSKI, LJ; HATHERLY, PA; STANKIEWICZ, M (JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, 1991)