DISSOCIATIVE EXCITATION OF ALIPHATIC-HYDROCARBONS (C2H2N, N=1,2,3) BYFAST ARGON ION IMPACT - ROVIBRATIONAL DISTRIBUTION OF CH(A(2)DELTA)

Emission spectra of CH(A(2) Delta-X(2)II) produced in collisions of Ar + (1.0-2.5 keV) with C2H2, C2H4 and C2H6 have been measured and the ro vibrational distributions of CH(A(2) Delta) have been obtained. The ro vibrational distributions of CH(A(2) Alpha Delta) are independent of t he 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 suggest ed that the CH(A(2) Delta) fragments are produced through dissociation of electronically excited states of C2H2n+ ( n = 1, 2, 3) ions.