A new instrument for kinetics and branching ratio studies of gas phase collisional processes at very low temperatures

A new instrument dedicated to the kinetic study of low-temperature gas phase neutral–neutral reactions, including clustering processes, is presented. It combines a supersonic flow reactor with vacuum ultra-violet synchrotron photoionization time-of-flight mass spectrometry. photoion–photoelectron coincidence detection scheme has been adopted optimize particle counting efficiency. The characteristics are detailed along its capabilities illustrated through few results obtained at low temperatures (<100 K) spectrum n-butane, formic acid dimer formation, and observation diacetylene molecules formed by reaction between C2H radical C2H2.