Dissociative excitation of aliphatic hydrocarbons (C2H2n: n = 1, 2, 3) by fast argon ion impact: Rovibrational distribution of CH(A2Δ) Original Research Article

Emission spectra of CH(A2Δ−X2Π) produced in collisions of Ar+ (1.0–2.5 keV) with C2H2, C2H4 and C2H6 have been measured and the rovibrational distributions of CH(A2Δ) have been obtained. The rovibrational distributions of CH(A2Δ) are independent of the collision energy and agree with those produced in e-C2H2n(n = 1, 2, 3) collisions at electron energies of 50 eV and higher. A comparison of the present results with the previous electron-impact data suggested that the CH(A2Δ) fragments are produced through dissociation of electronically excited states of C2H2n+∗(n = 1, 2, 3) ions.