PHOTON-STIMULATED ION DESORPTION OF DEUTERATED POLYSTYRENE THIN-FILMSINDUCED BY CORE EXCITATION

Photon stimulated ion desorption (PSID) of thin films of selectively d euterated polystyrene ([-CD2-CD(C6H5)-](n), [-CH2-CH(C6D5)-](n) and [- CD2-CD(C6D5)-](n)) have been investigated to reveal the mechanism of s urface photochemical reactions following core excitation. Desorbing io ns were measured using the time-of-flight mass spectrometer (TOF-MS) c ombined with a pulsed synchrotron radiation. From the total electron y ield spectrum and partial ion yield spectrum of each sample, it is con cluded that D+ ions are mainly desorbed from the phenyl group and the yield of D+ is enhanced at the C-D resonance. From the ion kinetic en ergy distribution obtained from analysis of the TOF spectrum, the ions desorbed from the phenyl group have different kinetic energy distribu tion. The results are discussed in connection with the mechanism of PS ID. (C) 1998 Elsevier Science B.V.