Vibration and Rotation ofN2+Excited by 10-65-keV Ions

Abstract

Cross sections for excitation of the [$B\left({{}_{}{}^2{}_{}{}^{}\Sigma _u^{}{}_{}{}^{}}^{+}\right)-X\left({{}_{}{}^2{}_{}{}^{}\Sigma _g^{}{}_{}{}^{}}^{+}\right)$] first negative bands of ${\mathrm{N}}_2^{+}$ resulting from impact of ${\mathrm{H}}^{+}$, ${\mathrm{D}}^{+}$, ${\mathrm{He}}^{+}$, ${\mathrm{Ne}}^{+}$, and ${\mathrm{N}}^{+}$ have been measured in the energy range 10-65 keV, and at pressures such that radiation occurs much sooner than subsequent collisions of the excited molecule. Intensity ratios of bands in this system and rotational distributions in the 3914-Å (0,0) and 4278-Å (0,1) bands have been directly measured and compared with those obtained from electron impact. Supplementary determinations of total charge-exchange cross sections have been made. Cross sections for excitation of Balmer alpha radiation in charge-exchange collisions of ${\mathrm{H}}^{+}$ and ${\mathrm{D}}^{+}$ with ${\mathrm{N}}_2$ have been measured in the same energy range. Little or no increase of vibration occurs in ${\mathrm{H}}^{+}$, ${\mathrm{D}}^{+}$, and $e^{-}$ impact, but a definite enhancement varying with ion velocity is produced by the heavier ions ${\mathrm{He}}^{+}$, ${\mathrm{Ne}}^{+}$, and ${\mathrm{N}}^{+}$. Rotation, however, remains in a thermal distribution at room temperature.