Temperature dependence of binary and ternary recombination of D3+ ions with electrons

Flowing and stationary afterglow experiments were performed to study the recombination of D(3)(+) 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 D(3)(+). We describe the observed ternary process by a mechanism with two rate determining steps. In the first step, a rotationally excited long-lived neutral D(3)* is formed in D(3)(+)-e(-) collisions. As the second step, the D(3)* collides with a helium atom that prevents autoionization of D(3)*. We calculate lifetimes of D(3)* formed from ortho-, para-, or metastates of D(3)(+) and use the lifetimes to calculate ternary recombination rate coefficients.