Dissociative recombination cross sections for NH4+ions and electrons

Cross sections for electron-N${\mathrm{H}}_4^{+}$ recombination have been measured for an electron energy range of $0.065\le E\le 2.00$ eV using a trapped-ion technique with an ion temperature of ∼340 K. The cross section $\sigma$ deduced from these measurements can be represented by $4.30\times {10}^{-16\mathrm{}}{E}^{-1.40\mathrm{}}$ for $0.050\le E\le 0.3$ eV and by $3.73\times {10}^{-17\mathrm{}}{E}^{-3.43\mathrm{}}$ for $E>\mathrm{}0.3\mathrm{}$ eV. There is a total uncertainty in the measurements of ±60%. Using a Maxwellian electron-velocity distribution, recombination-rate coefficients were calculated and compared with measurements of Huang, Biondi, and Johnsen.