Electron-photon polarization correlation study of neon, argon and krypton excitation by electron impact.
Item
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Title
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Electron-photon polarization correlation study of neon, argon and krypton excitation by electron impact.
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Identifier
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AAI9405608
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identifier
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9405608
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Creator
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Zheng, Shuanghai.
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Contributor
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Adviser: Kurt H. Becker
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Date
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1993
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Atomic | Chemistry, Physical
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Abstract
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The electron impact excitation of the 3s{dollar}\sp\prime{dollar} (1/2) {dollar}\sp0\sb1{dollar} state in neon, the 4s{dollar}\sp\prime{dollar} (1/2) {dollar}\sp0\sb1{dollar} state in argon and the 5s (3/2) {dollar}\sp0\sb1{dollar} state in krypton have been studied using the electron-photon polarization correlation technique. The two linear coherence parameters P{dollar}\sb1{dollar} and P{dollar}\sb2{dollar} have been measured and the alignment angle {dollar}\gamma{dollar} and the linear polarization P{dollar}\sp+\sb{lcub}\rm lin{rcub}{dollar} of the angular part of the collisionally induced excited state charge cloud were extracted from the measured P{dollar}\sb1{dollar} and P{dollar}\sb2{dollar} parameters. We measured P{dollar}\sb1{dollar} and P{dollar}\sb2{dollar} in neon at an impact energy of 50 eV, in argon at impact energies of 50 eV, 40 eV, 30 eV and 25 eV, and in krypton at impact energies of 50 eV and 30 eV and electron scattering angles up to 55{dollar}\sp\circ{dollar} in all cases. A comparison with theoretical predictions from first-order perturbative theories such as a Distorted Wave Born Approximation (DWBA) and a First Order Many Body Theory (FOMBT) was made. At 50 eV in neon and argon, the agreement between experiment and theory is generally good at small scattering angles up to 25{dollar}\sp\circ{dollar} and somewhat poorer at larger scattering angles. At 50 eV in krypton, the agreement between experiment and theory is generally good at scattering angles up to 40{dollar}\sp\circ{dollar}. The measurements in argon (40 eV, 30 eV, and 25 eV) generally follow the trend of the theoretical predictions, but it was found that the experimentally measured coherence parameters appear to be shifted towards larger scattering angles compared to the theoretical predictions as the impact energy is decreased. At 30 eV in krypton, very good agreement between experiment and theory was found over the entire range of electron scattering angles (up to 55{dollar}\sp\circ{dollar}). The level of agreement between experiment and theory indicates that the DWBA and FOMBT appear to provide a better description of the collision process for a more complex target. We also found that the alignment angle {dollar}\gamma{dollar} is the parameter which is perhaps least sensitive to the details of the collision.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
