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Author Hsu, C. ♦ Lu, K. T. ♦ Evans, M. ♦ Chen, Y. J. ♦ Ng, C. Y. ♦ Heimann, P.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ NEON ♦ PHOTOIONIZATION ♦ ARGON ♦ ULTRAVIOLET RADIATION ♦ RYDBERG STATES ♦ L-S COUPLING ♦ LIFETIME ♦ HIGH-RESOLUTION METHODS
Abstract Using the high resolution vacuum ultraviolet (vuv) photon source provided by the monochromatized undulator synchrotron radiation of the Chemical Dynamics Beamline at the Advanced Light Source, we have measured the photoionization efficiency (PIE) spectrum for Ne in the energy range of 21.56{endash}21.67 eV at a wavelength resolution of 0.3 meV [full width at half-maximum (FWHM)]. The PIE spectra for Ne obtained using 0.76 and 2.4 V/cm electric fields reveal autoionizing features attributable to the Rydberg states Ne[2{ital p}{sup 5}{ital ns}{prime}(1/2){sub 1}; {ital n}=14{endash}29] and Ne[2{ital p}{sup 5}{ital nd}{prime}(3/2){sub 1}; {ital n}=12{endash}35] converging to the spin{endash}orbit excited Ne{sup +}({sup 2}{ital P}{sub 1/2}) state. The positions of these Rydberg states are compared to previous experimental results and those calculated using the quantum defects and IE for Ne{sup +}({sup 2}{ital P}{sub 1/2}) given in Moore [Natl. Stand Ref. Data Ser. Natl. Bur. Stand. {bold 35} (1971)]. We have also observed mass analyzed threshold ions (MATI) for Ne formed in the Ne{sup +}({sup 2}{ital P}{sub 3/2,1/2}) states. For Ar, only the MATI peak for Ar{sup +}({sup 2}{ital P}{sub 3/2}) is observed. The failure to observe the MATI peak for Ar{sup +}({sup 2}{ital P}{sub 1/2}) is attributed to shorter lifetimes of high-{ital n} Ar[3{ital p}{sup 5}{ital ns}{prime}(1/2){sub 1}] and Ar[3{ital p}{sup 5}{ital nd}{prime}(3/2){sub 1}] Rydberg states compared to the minimum time required for separating the prompt Ar{sup +} ions from the field ionized Ar{sup +} ions in this experiment. The MATI peaks for Ne{sup +}({sup 2}{ital P}{sub 3/2,1/2}) achieves a resolution of 0.7 meV (FWHM). These MATI spectra for Ne and Ar reported here represent the first such studies made using a cw vuv light source and dc electric fields. {copyright} {ital 1996 American Institute of Physics.}
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-09-01
Publisher Department Lawrence Berkeley National Laboratory
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 105
Issue Number 10
Organization Lawrence Berkeley National Laboratory


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