19 research outputs found
Electron Impact Ionization Close to the Threshold: Classical Calculations
In this paper we present Classical Trajectory Monte Carlo (CTMC) calculations
for single and multiple electron ionization of Argon atoms and ions in the
threshold region. We are able to recover the Wannier exponents a for the
power-law behavior of the cross section s versus excess energy: the exact value
of the exponent as well as the existence of its saturation for multiple
ionization appear to be related to how the total binding energy is shared
between target electrons.Comment: 9 pages. To be published in Journal of Physics
Recommended from our members
Ionization energy studies for Cl2O monomers and dimers
Electron ionization cross sections measured close to threshold are reported for the Cl2O monomer and dimer using a high resolution electron impact apparatus. Besides measuring the appearance energies (AEs) (Cl2O+/Cl2O) 11.04?0.06 eV, (ClO+/Cl2O) 12.29 ? 0.14 eV, (Cl+/Cl2O) 16.11 ? 0.35 eV, (O+/Cl2O) 15.15 ? 0.14 eV we have also determined, for the first time, the dimer AE (Cl2O)2+/(Cl2O)2 10.47?0.2 eV. From the data we derive a lower bound of the bond energy of 0.71?0.3 eV for (Cl2O)2+ which is similar to that of other dimer ions. Quantum chemical calculations carried out to complement the present study support the experimental data
Recommended from our members
Electron impact ionization studies for SF5CF3
Electron impact ionization cross sections measured close to threshold are reported for the newly discovered greenhouse gas SF5CF3. No stable parent ion is detected but several cations are detected and their appearance energies (AE) have been measured. The AE (CF3+/SF5CF3) 12.87?0.10 eV is in excellent agreement with a recently reported value derived from a photoelectron-photoion coincidence experiment. Other ion thresholds are: AE (CF+/SF5CF3) 24.44?0.10 eV, AE (CF2+/SF5CF3) 17.80?0.50 eV; AE (SF+/SF5CF3) 12.66?0.20 eV; AE (SF3+/SF5CF3) 14.48?0.10 eV; AE (SF5+/SF5CF3) 13.16?0.60 eV. Two thresholds are suggested for AE (SF4+/SF5CF3) 16.10?0.30 and 12.10?0.30 eV. A tentative assignment of an AE for SF2+/SF5CF3 of 15.6?1.0 is also given. These results confirm that SF5CF3 is unlikely to be photolysed in the lower stratosphere and therefore will have a long lifetime against solar photodissociation
Effective degradation of uracil by electron of ultralow enrgies: implications for the molecular mechanism in radiation damage
IPMInternational audienc
Charge transfer dynamics in Ar+ + CO
Differential cross sections for the charge transfer reaction between Ar(+)and CO have been measured using three-dimensional velocity map imaging in a crossed beam setup at the two relative collision energies 0.55 and 0.74 eV. We find dominant forward scattering with CO(+)product ions predominantly in the vibrational levels=6,7 of the electronic ground state X. This is indicative of a direct resonant mechanism for the two argon spin-orbit states. At both collision energies also an isotropic distribution with product ions exhibiting high internal excitation is observed. This is more pronounced at the higher collision energy, where the first electronically excited state Abecomes accessible. We conclude that the A-state is partially populated by the product ions at 0.74 eV collision energy and suggest that the isotropic distribution stems from the formation of a charge-transfer complex, in concurrence with previously performed studies. [GRAPHICS]