Abstract
Flowing and stationary afterglow experiments were performed to study the recombination of D3+ ions with electrons at temperatures from 77 to 300 K. A linear dependence of apparent (effective) binary recombination rate coefficients on the pressure of the helium buffer gas was observed.
Binary ($D_3^+ + e$) and ternary ($D_3^+ + e + He$) recombination rate coefficients were derived. The obtained binary rate coefficient agrees with recent theoretical values for dissociative recombination of D3+.
We describe the observed ternary process by a mechanism with two rate determining steps. In the first step, a rotationally excited long-lived neutral D3* is formed in $D_3^+ + e$ collisions.
As the second step, the D3* collides with a helium atom that prevents autoionization of D3*. We calculate lifetimes of D3* formed from ortho-, para-, or metastates of D3+ and use the lifetimes to calculate ternary recombination rate coefficients.