Multichannel-quantum-defect-theory treatment of reactive collisions between electrons and BeH+

Abstract

A theoretical treatment of dissociative recombination (DR), vibrational excitation, and vibrational deexcitation of the BeH${}^{+}$ ion in its four lowest vibrational states ($X{\phantom{\rule{0.16em}{0ex}}}^{1}{\ensuremath{\Sigma}}^{+},{v}_{i}^{+}=0,1,2,3$) is reported. The multichannel quantum defect theory is used to determine cross sections and rate coefficients. Three electronic symmetries of BeH (${}^{2}\ensuremath{\Pi}$, ${}^{2}{\ensuremath{\Sigma}}^{+}$, and ${}^{2}\ensuremath{\Delta}$) have been included in the calculations. At low energies the DR is dominated by capture into states of ${}^{2}\ensuremath{\Pi}$ symmetry. Satisfactory agreement with results obtained using the wave packet approach is reached at intermediate energies despite significant differences at low energies. Cross sections and rate coefficients suitable for the modeling of the kinetics of BeH${}^{+}$ in fusion plasmas and in the stellar atmospheres are presented and discussed.