The paper "Capacitively coupled hydrogen plasmas sustained by tailored voltage waveforms: vibrational kinetics and negative ions control" has been published in Plasma Sources Science and Technology (DOI).
A comprehensive hybrid model of a hydrogen capacitively coupled plasma, including a detailed description of the molecular vibrational kinetics, has been applied to the study of the effect of tailored voltage waveforms (TVWs) on the production kinetics and transport of negative ions in these discharges. Considering the chemical reactivity of H− ions, the possibility of a purely electrical control of the negative ion cloud in a reactor operating with a feedstock gas diluted by hydrogen may find interesting applications. This is the first study of vibrational kinetics in the context of TVWs in molecular gases.
Authors of the paper are P. Diomede, B. Bruneau, S. Longo, E. Johnson and J.-P. Booth.
Dissociative attachment rate as a function of the position across the discharge gap and the quantum number of the vibrational state of the hydrogen molecule. Negative hydrogen ions are produced by dissociative electron attachment of vibrationally excited molecules. An opposite asymmetry is seen in the contributions from low vibrational levels as opposed to higher levels, due to opposing trends in the plasma density and the electron energy distribution (EEDF) asymmetry.