Dissociative Excitation of Acetylene Induced by Electron Impact: Excitation-emission Cross-sections

TL;DR

This study investigates the optical emission spectrum of acetylene excited by monoenergetic electrons, measuring excitation-emission cross sections and energy thresholds for dissociative processes, revealing dominant atomic and molecular emissions.

Contribution

It provides new measurements of absolute excitation-emission cross sections and energy thresholds for dissociative channels in electron-impact excitation of acetylene.

Findings

Dominant atomic lines of H and C observed

Molecular bands of CH, CH+, and C2 identified

Continuum emission of C2H detected

Abstract

The optical emission spectrum of acetylene excited by monoenergetic electrons was studied in the range of 190 nm to 660 nm. The dissociative excitation and dissociative ionization associated with excitation of the ions initiated by electron impact were dominant processes contributing to the spectrum. The spectrum was dominated by the atomic lines H, C and molecular bands of CH, CH, CH+, and C2. Besides the discrete transitions, we have detected the continuum emission radiation of ethynyl radical C2H. For most important lines and bands of the spectrum we have measured absolute excitation-emission cross sections and determined the energy thresholds of the particular dissociative channels.