A mass-spectrometric investigation of polymerization processes inuced by microwave irradiation in methane, methane—argon and methane—krypton mixtures during the formation of pyrolytic carbon

Mass Spectrometry of Free Radicals

“…The difference in ion distribution has been attributed to the difference in electron energy acting in the ionization processes and to the difference in the kinetic energy of primary ions, favoring in the latter radial sampling configuration ion−molecule reactions with an increased probability for condensation reactions. Polymerization reactions in pure methane discharge were investigated by Marcus and Platzner, using microwave irradiation and higher pressure conditions (0.5−5 Torr) compared to Vasile and Smolinsky, and confirmed the observance of condensation reactions of C 2 ions, mainly C 2 H 2 + and C 2 H 3 + , with methane and C 2 neutrals. However, radical species with the methylene radical CH 2 as the dominant reactant, and hydrogen-deficient ions CH 2 + and CH + were proposed to intervene in primary processes which lead to the formation of the previously detected C 2 precursor ions.…”