Pulsed field ionization-photoelectron photoion coincidence spectroscopy with synchrotron radiation: The heat of formation of the C2H5+ ion
2000
Pulsed field ionization photoelectron (PFI-PE) spectroscopy combined with ion
coincidence detection has been used with multi-bunch synchrotron radiation at the
Advance Light Source (ALS) to energy select ions and to measure their breakdown
diagram. The resolution for ion state selection achieved with Ar+ (2P3/2,1/2) employing
this PFI-PE-photoion coincidence apparatus is 0.6 meV (full width at half maximum). The
production of C2H5+ from C2H5Br was investigated near the dissociative photoionization limit
with this pulsed field ionization-threshold photoelectron photoion coincidence (PFI-PEPICO)
scheme. Although the PFI-PE spectra of C2H5Br, C2H5I, and benzene show that
the production of ions in the Franck–Condon gap regions is quite low, the selectivity for PFI-PE detection and the suppression of prompt electrons is such that we can detect 1 PFI-PE
out of 25000 total electrons s−1. The derived C2H5+ heat of formation from the analysis
of the C2H5Br+ breakdown diagram and a critical analysis of other results is 900.5±2.0
kJ mol−1 at 298 K, or 913.2±2.0 kJ mol−1 at 0 K. This leads to an ethylene proton
affinity at 298 K of 682.0 kJ mol−1. The measured IE of C2H5Br is 10.307 eV.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
20
References
31
Citations
NaN
KQI