Electron impact ionization of Ar10+

Total and single differential cross sections have been calculated for electron impact ionization of Ar10+(1s22s22p4)3Pe using a method that combines the distorted-wave Born approximation and R-matrix theory. In this method, the incident/scattered electron is described by the distorted-wave Born approximation, while both the initial bound state and the final continuum states are expanded in terms of an R-matrix basis. Eight states of the final Ar11+ ion are considered, namely 1s22s22p3 4So 2Do 2Po and 1s2 2s2p4 4Pe 2De 2Se 2Pe 2Po . Up to the 24- pole components of the interaction with ionizing electron were included, giving ten distinct Ar10+ continuum symmetries. We calculated single differential cross sections summed over final ionic states, as a function of the energy loss. These cross sections exhibit considerable structure due to autoionizing resonances. Total cross sections for production of Ar11+ in each of the eight states are presented for impact energies from threshold energy at 19.8 au to 200 au. Our theoretical values for the total cross section are in good agreement with recent experimental results.Total and single differential cross sections have been calculated for electron impact ionization of Ar10+(1s22s22p4)3Pe using a method that combines the distorted-wave Born approximation and R-matrix theory. In this method, the incident/scattered electron is described by the distorted-wave Born approximation, while both the initial bound state and the final continuum states are expanded in terms of an R-matrix basis. Eight states of the final Ar11+ ion are considered, namely 1s22s22p3 4So 2Do 2Po and 1s2 2s2p4 4Pe 2De 2Se 2Pe 2Po . Up to the 24- pole components of the interaction with ionizing electron were included, giving ten distinct Ar10+ continuum symmetries. We calculated single differential cross sections summed over final ionic states, as a function of the energy loss. These cross sections exhibit considerable structure due to autoionizing resonances. Total cross sections for production of Ar11+ in each of the eight states are presented for impact energies from threshold energy at 19.8 au to 200 au. Our theoretical values for the total cross section are in good agreement with recent experimental results

Wavelet phase evaluation extended to digital speckle patterninterferometry

A wavelet algorithm developed to improve metrology based on electronic speckle pattern intérferometry (ESPI) is presented. The wavelet algorithm is based on the calculation of the continuous wavelet transform of a modulated speckle correlation fringes .The Paul wavelet is used , the extraction of the maximum scales of the modulus of the wavelet transform leads simply to the phase gradient distribution. The advantage of the method is to provide phase distribution, with a high accuracy, from a single interferogram without unwrapping step.A wavelet algorithm developed to improve metrology based on electronic speckle pattern intérferometry (ESPI) is presented. The wavelet algorithm is based on the calculation of the continuous wavelet transform of a modulated speckle correlation fringes .The Paul wavelet is used , the extraction of the maximum scales of the modulus of the wavelet transform leads simply to the phase gradient distribution. The advantage of the method is to provide phase distribution, with a high accuracy, from a single interferogram without unwrapping step

The Formation of H+ From H- By Electron-impact

New absolute cross section measurement for the reaction H- + e --> H+ + 3e- is reported for interaction energies from threshold to 2 keV by using the animated crossed beam method. The present results confirm the disagreement between the previous results of this laboratory and the results of Peart et al

Electron impact double ionization of krypton ions (q=14-17)

Absolute cross sections for electron impact double ionization of krypton ions Krq+ (q = 14-17) have been measured from threshold to 5 keV. The animated crossed beam method has been employed. Direct double ionization is seen to reduce strongly along the isonuclear sequence. Ionization-autoionization from the inner L-shell is seen to be the dominant process. It is roughly approximated by the semi-empirical Lotz formula assuming total autoionization of the ionic intermediate states. Resonant capture and excitation processes implying the L-shell are also obtained for charge states 14-16

Asymmetrical dissociative ionization of N-2(+) and O-2(+) by electron impact

Absolute cross sections for electron impact formation of N2+ from N-2(+) and O-2(+) from O-2(+) have been measured in the energy range from below threshold to approximately 2000 eV. The animated crossed beams method has been employed. The cross sections at the maximum are found robe 8.4 x 10(-19) cm(2) and 12.1 x 10(-19) cm(2), respectively and the corresponding threshold energies are determined to be 43.7 +/- 0.5 eV and 36.8 +/- 0.5 eV. From an energy analysis of the collected dissociation products (N2+ and O2+), the maximum centre of mass energy available is found to be 13.0 +/- 1 eV and 14.6 +/- 1 eV, respectively

Electron impact ionization and dissociation of CO2+ to C+ and O+

Absolute cross sections for electron impact ionization and dissociation of CO2+ to form C+ and O+ fragments are measured in the energy range from threshold to 2500 eV. The animated crossed-beams method has been employed. The ionization cross section shows a maximum of 4.79 x 10(-17) cm(2) at 130 eV and the corresponding threshold is found in good agreement with previous measurements. Both dissociation cross sections are shown to exhibit wide plateaux which are of the same order of magnitude. In addition, these cross sections almost coincide above 100 eV. The threshold energy and kinetic energy released are determined for both the production of C+ and O+. They are found in good agreement with the previously published data obtained in electron impact ionization experiments of neutral CO2

Electron-impact single ionization of krypton ions (q=12-18)

Absolute cross sections for electron-impact single ionization of krypton ions Krq+ (q = 12-18) have been measured. The animated crossed-beam method has been applied. The measurements cover the energy range from threshold to about 5.5 keV. The presence of ions formed in metastable states is observed for Kr18+, Kr16+ and Kr14+. Inner-shell excitation from the 2s, 2p, 3s and 3p subshells followed by autoionization is seen to play a dominant role for this reaction over the whole energy range. The importance of these excitation-autoionization processes explains the large underestimation of cross sections from the available theoretical and semi-empirical estimations which include direct processes only

Digital optical particle sizing instrument based on Chin-Shifrin inversion

In this paper, a new optical particle-sizing instrument is presented for determination of particle sizes from 1 to 100 mu m. Based on the Chin-Shifrin inversion method and digital image processing, the new system gives very accurate results for a calibrated testing sample and industrial cement particles. (C) 2007 Elsevier GmbH. All rights reserved