Kinetic reactions involving the titanium atoms in an argon-titanium hollow cathode afterglow

Abstract

We have used the pulsed afterglow technique in a hollow cathode titanium-argon plasma to study the mechanisms of production and loss of the neutral and ionized titanium species. From the measurement of the decay time of the ground state titanium atom Ti(a 3F J ) density, determined by the optical absorption technique, we have deduced the value of the diffusion coefficient of titanium atoms in argon at 300 K, D 0( Ti- Ar) = 3.1 × 10 18 atoms cm -1 s -1. The analysis of the emission intensity from the excited levels of titanium ion seems to point to the fact that the principal mechanism for the production of the (Ti +) ∗ is a charge transfer process, involving Ar + ions, rather than the Penning ionization by argon metastable atoms. The excited levels of the titanium atom are populated by electron-ion recombination involving the Ti + ions.