Reprint of: Pyrolysis of ethanol studied in a new high-repetition-rate shock tube coupled to synchrotron-based double imaging photoelectron/photoion coincidence spectroscopy

Shock tube techniques for kinetic studies are continuously evolving driven by advances in kinetic modeling and detection techniques. An innovative category of shock tubes has been recently developed for use at Synchrotron facilities. In this work, a new high-repetition-rate shock tube (HRRST) was constructed to employ synchrotron-based double imaging photoelectron/photoion coincidence spectroscopy (i2PEPICO) at the beamline DESIRS of the SOLEIL synchrotron. The shock tube design and performance (pressure profiles, repeatability of operations) are presented for the first time together with the detailed description of the coupling with the molecular beam end-station holding the i2PEPICO spectrometer. The first experimental results with the HRRST/i2PEPICO on ethanol pyrolysis are grouped based on four different experimental conditions, each highlighting functionality of this novel experimental system. Experiments were performed at temperatures between 1232 K and 1525 K, pressures between 6.2 bar and 7.5 bar, with 2.7% or 0.25% ethanol in argon, and photon energy of 10.0 eV or 11.0 eV. The results are supported by kinetic analyses with the CRECK model. This study shows the potential of the HRRST/i2PEPICO combination for obtaining detailed mechanistic and kinetic data for complex chemical systems. Mass spectra, photoelectron spectra and time-resolved species profiles were obtained for a wide variety of species from methyl radicals to large polyaromatic hydrocarbons. The different experimental conditions studied indicate how future experiments can be designed to target key regimes facilitating the elucidation of desired kinetic and mechanistic data.