Emission Spectrum of Acetylene by Controlled Electron Impact

Abstract

Abstract Emission spectra of C2H2 and C2D2 excited by collisions with electrons of 7–20 eV show a broad and diffuse band in the 240–400 nm region and this band was assigned to the S1(lower vibrational levels)–S0 transition of acetylene on the basis of its .wavelength, excitation function (threshold: 5.5 eV) and lifetime (323±30 ns). Their emission cross sections are on the order of 10−19 cm2. Among intense fragment emissions at higher electron energies, band of C2H has also been observed and its lifetime is 3.9±0.8 μs.