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University of Nebraska - Lincoln

Ilya Fabrikant Publications

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Dissociative Electron Attachment And Vibrational Excitation Of Cf3cl: Effect Of Two Vibrational Modes Revisited, Michal Tarana, Karel Houfek, Jiri Horacek, Ilya I. Fabrikant Jan 2011

Dissociative Electron Attachment And Vibrational Excitation Of Cf3cl: Effect Of Two Vibrational Modes Revisited, Michal Tarana, Karel Houfek, Jiri Horacek, Ilya I. Fabrikant

Ilya Fabrikant Publications

We present a study of dissociative electron attachment and vibrational excitation processes in electron collisions with the CF3Cl molecule. The calculations are based on the two-dimensional nuclear dynamics including the C-Cl symmetric stretch coordinate and the CF3 symmetric deformation (umbrella) coordinate. The complex potential energy surfaces are calculated using the ab initio R-matrix method. The results for dissociative attachment and vibrational excitation of the umbrella mode agree quite well with experiment whereas the cross section for excitation of the C-Cl symmetric stretch vibrations is about a factor-of-three too low in comparison with experimental data.

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Effects Of Two Vibrational Modes In The Dissociative Electron Attachment To Cf3cl, Michal Tarana, Pawel Wielgus, Szczepan Roszak, Ilya I. Fabrikant Jan 2009

Effects Of Two Vibrational Modes In The Dissociative Electron Attachment To Cf3cl, Michal Tarana, Pawel Wielgus, Szczepan Roszak, Ilya I. Fabrikant

Ilya Fabrikant Publications

We present a study of multimode effects in dissociative electron attachment to CF3Cl molecules using a time-independent version of the local complex potential theory. Symmetric stretch C-Cl vibrations v3 and symmetric deformation (or so-called umbrella) vibrations v2 are included. The neutral and anion potential energy surfaces are calculated using the second-order Møller-Plesset perturbation theory with an empirical adjustment of the vertical attachment energy. The final-state vibrational distribution in the CF3(v2) fragment is dominated by the v2=2 state. We also find an increase in the total cross section as compared with …

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Electron Attachment To Cl2 From 300 To 1100 K: Experiment And Theory, Jeffrey Friedman, Thomas Miller, Linda Schaffer, A. A. Viggiano, Ilya I. Fabrikant Jan 2009

Electron Attachment To Cl2 From 300 To 1100 K: Experiment And Theory, Jeffrey Friedman, Thomas Miller, Linda Schaffer, A. A. Viggiano, Ilya I. Fabrikant

Ilya Fabrikant Publications

Rate constants for dissociative electron attachment to Cl2 have been measured from 300 to 1100 K in a high-temperature flowing-afterglow Langmuir-probe apparatus. R-matrix calculations have been carried out which compare well with the present measurements with possible deviation at the highest temperatures. The attachment rate constants do not show Arrhenius behavior. The temperature dependence of the calculated rate constants for successive vibrational levels provides insight as to this behavior. While the lowest vibrational level of Cl2 dominates attachment at low temperatures, the rate constant is not flat with temperature because of the p-wave character of the …

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On The Validity Of The Arrhenius Equation For Electron Attachment Rate Coefficients, Ilya I. Fabrikant, Harmut Hotop Jan 2008

On The Validity Of The Arrhenius Equation For Electron Attachment Rate Coefficients, Ilya I. Fabrikant, Harmut Hotop

Ilya Fabrikant Publications

The validity of the Arrhenius equation for dissociative electron attachment rate coefficients is investigated. A general analysis allows us to obtain estimates of the upper temperature bound for the range of validity of the Arrhenius equation in the endothermic case and both lower and upper bounds in the exothermic case with a reaction barrier. The results of the general discussion are illustrated by numerical examples whereby the rate coefficient, as a function of temperature for dissociative electron attachment, is calculated using the resonance R-matrix theory. In the endothermic case, the activation energy in the Arrhenius equation is close to …

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Highly Resolved Absolute Cross-Sections For Dissociative Electron Attachment To Sf5cf3, K. Graupner, L. M. Graham, T. A. Field, Christopher A. Mayhew, Ilya I. Fabrikant, T. M. Miller, M. Braun, M.-W. Ruf, Harmut Hotop Jan 2008

Highly Resolved Absolute Cross-Sections For Dissociative Electron Attachment To Sf5cf3, K. Graupner, L. M. Graham, T. A. Field, Christopher A. Mayhew, Ilya I. Fabrikant, T. M. Miller, M. Braun, M.-W. Ruf, Harmut Hotop

Ilya Fabrikant Publications

Using two complementary experimental methods, we have measured partial (mass-resolved) cross-sections for dissociative electron attachment to the molecule trifluoromethyl sulfurpentafluoride (SF5CF3) at the gas temperature TG = 300K over a broad range of electron energies (E = 0.001–12 eV).

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Observation Of P-Wave Threshold Behavior In Electron Attachment To F2 Molecules, M. Braun, M.-W. Ruf, Ilya I. Fabrikant, H. Hotop Dec 2007

Observation Of P-Wave Threshold Behavior In Electron Attachment To F2 Molecules, M. Braun, M.-W. Ruf, Ilya I. Fabrikant, H. Hotop

Ilya Fabrikant Publications

Using the high resolution laser photoelectron attachment method, we demonstrate that the cross section for F- formation due to electron capture by F2 (X1Σg+) molecules at very low energies exhibits p-wave threshold behavior. This finding confirms the theoretical expectation that low-energy attachment to F2 proceeds through the F2-(2 Σu+) p-wave shape resonance in contrast with previous experimental claims for s-wave threshold behavior.

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Dissociative Electron Attachment On Surfaces And In Bulk Media, Ilya I. Fabrikant Jan 2007

Dissociative Electron Attachment On Surfaces And In Bulk Media, Ilya I. Fabrikant

Ilya Fabrikant Publications

A theory of dissociative electron attachment to molecules condensed at surfaces and embedded within bulk media is developed. The theory of low-energy electron diffraction is used to obtain the width for electron-molecule resonance scattering in the condensed phase from the width for the gas phase. It is then employed for the calculation of dissociative attachment in the framework of the nonlocal complex potential theory. Specific calculations using the effective mass approximation are carried out for electron attachment to CH3Cl and CF3Cl molecules physisorbed on the surface of a Kr film. The role of image states and …

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