Electron-stimulated field desorption of diatomic and triatomic hydrogen

Abstract

Precursor structures of high-energy ${\mathrm{H}}_{2}^{+}$ and ${\mathrm{H}}_{3}^{+}$ field ions have been detected by retarding-potential analysis, and the electron-stimulated field desorption of adsorbed ${\mathrm{H}}_{2}$ and ${\mathrm{H}}_{3}$ is proposed as the most plausible origin. From energy distributions of electron-stimulated field desorbed ${\mathrm{Ne}}^{+}$ and field desorbed ${\mathrm{H}}_{3}^{+}$, taken on W(111) at the same field strength and surface temperature, we infer the presence of a linear ${\mathrm{H}}_{3}$ adsorbed in an upright position on the field emitter surface.