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Štefan Matejčík Comenius University Bratislava, Slovakia. Electron Impact Ionization of selected hydrocarbon molecules. Stephan Denifl Fabio Zappa Univ. Innsbruck. Coworkers. Dušan Kubala Jaroslav Kočíšek Peter Papp Pavel Mach Jan Urban. Electron impact ionisation - EII.
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Štefan Matejčík Comenius University Bratislava, Slovakia Electron Impact Ionization of selected hydrocarbon molecules
Stephan Denifl Fabio Zappa Univ. Innsbruck Coworkers • Dušan Kubala • Jaroslav Kočíšek • Peter Papp • Pavel Mach • Jan Urban
Electron impact ionisation - EII • e + M → M+ + 2e • e + M → X+ + (M-X) + 2e • Appearance energies • Partial cross sections for EII
high Tg Electron impact ionization low Tg σ E
Molecules studied in 2007 and 2008 Experiment C2D6 CH3D CD4 C3H8 C3H6D2 Theory BenHm
Ar and Ne cross sections R. Rejoub, B.G. Lindsay, R.F. Stebbings, Phys. Rev. A, 65 (2002)042713.
EII to CD4 cross sections Tarnovsky et al. J. Phys. B: At. Mol. Opt. Phys. 29 (1996) 139
Tarnovsky et al. J. Phys. B: At. Mol. Opt. Phys. 29 (1996) 139
VIE VIE
Ionization cross sections calculations • Kim-s BEB (binary encounter Bethe) theory [W. Hwang, Y.-K. Kim, M. E. Rudd, J. Chem. Phys. 104, 2956 (1996)], • HF/6-31++G(2df,2pd) orbital kinetic energies • OVGF/6-31++G(2df,2pd) ionization potentials for ionization from valence orbitals • For core orbitals IP the HF values were used (their contribution to total cross section in studied region is very small).
Ionization potential of Be5Hn clusters as a function of “n”. Most stable cluster of given stechiometry. Method: MP4(SDTQ)/6-31++G(2df,2pd) Geometry: MP2/6-31++G(2df,2pd)
Total ionization cross sections for Be5Hn clusters Increasing hydrogen content in mixed clusters increases IP and decrease cross section for ionization
Conclusions • Measured partial cs for EII to • CH3D • CD4 • C2D6 • C3H8 • Appearance energy – C3H6D2 • Calculated • ionization energies Be5Hn • EII total cross sections Be5Hn