Low-energy electron collisions with BH+

Abstract

BH+ ions are expected to play an important role in boron-containing plasmas relevant to fusion environments such as ITER, where low-energy electrons drive a variety of inelastic and reactive scattering processes. In particular, dissociative recombination, vibrational excitation, and de-excitation strongly influence the ion balance and energy distribution in such plasmas. We present a theoretical study of electron collisions with BH+ using a combination of ab initio electronic structure calculations and electron scattering methods. Potential energy curves for bound states of BH and BH+ are obtained using multireference configuration interaction, while autoionization widths of electronic resonant states are computed with the complex Kohn variational method. The collision dynamics is modeled within multichannel quantum defect theory, including both the “crossing”—i.e., Feshbach-resonances-mediated—and the “non-crossing”—i.e., Rydberg-mediated—mechanisms. Cross sections and thermal rate coefficients for the processes are provided for the lowest vibrational levels of BH+ and its isotopologues—BD+ and BT+—showing significant isotope effects, especially at low electron temperatures.