Vibrational relaxation and dissociative recombination ofH2+induced by slow electrons

Abstract

We present calculations of cross sections and rate coefficients for the dissociative recombination of ${\mathrm{H}}_{2}^{+}$ ions initially in $v=0--6$ vibrational levels, together with rate coefficients for the competing electron-induced vibrational deexcitation. We used the multichannel quantum defect theory with a second-order treatment of the K matrix, and show that electronic interactions dominate not only the dissociative recombination but also the vibrational relaxation induced by slow electrons. Most of our rate coefficients for dissociative recombination are in good agreement with the measurements at the TSR storage ring [S. Krohn et al., Phys. Rev. A 62, 032713 (2000)]. On the contrary, our rates for vibrational deexcitation, close to former results obtained by R-matrix calculations [B. K. Sarpal and J. Tennyson, Mon. Not. R. Astron. Soc. 263, 909 (1993)], are smaller by up to one order of magnitude than the experimental values which are deduced from the time evolution of the vibrational populations, measured by the Coulomb explosion imaging method.