Angle-resolved, mass-selected ion spectroscopy of carbon K-shell excited CF3CCH
Total photoabsorption cross section and peak assignments were presented for CF3CCH in the carbon K-shell region. Anisotropy parameters of fragment ions obtained by means of an angle-resolved mass spectrometer were helpful to the peak assignments of the K-shell excitation into π and σ states. Kinetic energy distributions of the H+, CH+, C2H+ and CF2+ fragment ions were fitted using a Gaussian function with one peak, while those of the CF3+ fragment ion were analyzed by use of two and three components for the C K-shell excitation of the CF3 and C2H sides, respectively. The kinetic energy distribution of the CF3+ fragment ion was reasonably understood by the consideration that photofragmentation of the K-shell excited molecule probably competes with intramolecular energy relaxation in which the CF3 group works as an effective energy reservoir. The yields of the CFn+ (n = 2,3), C3FH2+ and C3F2H2+ ions were dependent on the site of excitation.
Copyright (c) 2004 Elsevier B.V.