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

TL;DR

This paper introduces a novel instrument combining a supersonic flow reactor with VUV synchrotron photoionization mass spectrometry, enabling detailed kinetic and branching ratio studies of low-temperature gas phase reactions, including clustering.

Contribution

It presents a new experimental setup that enhances the study of low-temperature gas phase reactions with improved detection and analysis capabilities.

Findings

Successful detection of formic acid dimer formation

Observation of diacetylene molecules from C2H radical reactions

Photoionization spectrum of n-butane at low temperatures

Abstract

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 (VUV) synchrotron photoionization time of flight mass spectrometry. A photoion-photoelectron coincidence detection scheme has been adopted to optimize the particle counting efficiency. The characteristics of the instrument are detailed along with its capabilities illustrated through a few results obtained at low temperatures (< 100 K) including a {photoionization spectrum} of n-butane, the detection of formic acid dimer formation as well as the observation of diacetylene molecules formed by the reaction between the C$_2$H radical and C$_2$H$_2$.