VUV photoionization of (CH3I)(n) (n=1-4) molecules

The photoionization efficiency (PIE) spectra of the ions produced by the VU V synchrotron radiation photoionization of (CH3I)(n) (n = 1-4) molecules in the photon energy range of 8-35 eV have been measured by using time-off-li ght (TOF) mass spectrometer with supersonic cooling techniques. The appeara nce potentials (APs) of all the observed fragment ions have been determined from the PIE curves. Based on these data, the bond energies (D-0), standar d formation enthalpies (Delta (f)H(0)degrees) and proton affinities (PA(0)) of the related fragments were obtained. Several autoionization structures of CH3I in the PIE spectrum of CH3I+ were assigned. (C) 2001 Elsevier Scien ce BY. All rights reserved.