Author/Authors :
Denifl، نويسنده , , S. and Matej??k، نويسنده , , S. and Skalny، نويسنده , , J.D. and Stano، نويسنده , , M. and Mach، نويسنده , , P. and Urban، نويسنده , , J. and Scheier، نويسنده , , P. and M?rk، نويسنده , , T.D. and Barszczewska، نويسنده , , W.، نويسنده ,
Abstract :
The threshold behavior of the cross-section for positive ions formed via electron impact ionization of propane (C3H8) has been studied in a crossed electron/neutral beams apparatus with mass spectroscopic analysis of the ions. Appearance energies (AEs) for two states (Cs and C2v) of the parent ion C 3 H 8 + / C 3 H 8 (AE(Cs) = 10.51 ± 0.05 eV and AE(C2v) = 10.96 ± 0.05 eV) and for six additional fragment ions have been determined. Moreover, for the four most abundant cations appearance energies have been measured at two different temperatures (290 and 690 K) showing a decrease of the appearance energies with increasing gas temperature. The present experimental results are compared with appearance energies calculated using high level quantum chemical methods (G3, G3B3 and CBS-QB3).
