State Selective Recombination of H3+ Ions at Low Temperatures: Kinetic Modelling and Experimental Study on Plasma Deexcitation
2022
Abstract
We have measured the reaction rate coefficient for Penning ionization of argon atoms in collisions with metastable helium atoms. This experiment is motivated by the planned studies of the state-selective dissociative recombination (DR) rate of ortho- and para-H3+ ions with electrons under 50 K.
A stationary afterglow (SA) apparatus was utilized in present studies. The measurement of the number densities of ions and of electrons is carried out by continuous wave cavity ring-down spectroscopy and microwave diagnostics, respectively.
The measured Penning ionization reaction rate coefficient was of the order of 10-10 cm3s-1, which is in agreement with the typical rates for Penning ionization.