André Canosa | Searcharxiv

arXiv2020

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 (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$_2$.

physics.chem-ph↗

arXiv2010

Kinetics and Dynamics of the S(^1D_2) + H_2 \to SH + H Reaction at Very Low Temperatures and Collision Energies

We report combined studies on the prototypical S(^1D_2) + H2 insertion reaction. Kinetics and crossed-beam experiments are performed in experimental conditions approaching the cold energy regime, yielding absolute rate coefficients down to 5.8 K and relative integral cross sections to collision energies as low as 0.68 meV. They are supported by quantum calculations on a potential energy surface treating long range interactions accurately. All results are consistent and the excitation function behavior is explained in terms of the cumulative contribution of various partial waves.

physics.chem-ph↗