First Spectroscopic Observation of theCΠu2Excited State ofH2+

Abstract

The translational-energy spectroscopy is used to search for the first transitions from the $X^{2}\ensuremath{\Sigma}_{\mathrm{g}}$ ground state of ${\mathrm{H}}_{2}^{+}$ to bound excited electronic states. Electron impact is used to create the ${\mathrm{H}}_{2}^{+}$ ions from C${\mathrm{H}}_{4}$. It is known that electron impact on C${\mathrm{H}}_{4}$ creates ${\mathrm{H}}_{2}^{+}$ ions highly rwotationally excited. A transition is observed centered at 10.2 eV. The observed peak is assigned to the optically allowed transitions $X^{2}{\ensuremath{\Sigma}}_{\mathrm{g}}^{+}\ensuremath{\rightarrow}C^{2}\ensuremath{\Pi}_{\mathrm{u}}$.