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Author Beck, Kenneth M. ♦ Mccarthy, Maureen I. ♦ Hess, Wayne P.
Source SpringerLink
Content type Text
Publisher Springer-Verlag
File Format PDF
Copyright Year ©1997
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Chemistry & allied sciences
Subject Keyword CaCO$_{3}$ ♦ isoelectronic ♦ isostructural crystals ♦ NaNO$_{3}$ ♦ photostimulated desorption (PSD) ♦ Optical and Electronic Materials ♦ Characterization and Evaluation of Materials ♦ Electronics and Microelectronics, Instrumentation ♦ Solid State Physics and Spectroscopy
Abstract Calcium carbonate and sodium nitrate are isostructural crystals in which the covalently bonded polyatomic anions are also isoelectronic, however, the chemical properties of these crystals are distinctly different. In this study, we report results involving the photostimulated desorption (PSD) of neutral CO and O($^{3}$P) products from geologic calcite (CaCO$_{3}$) using low laser fluence at 193 nm. Product states are probed using (2+1) resonance enhanced multiphoton ionization for both neutrals. The CO products display a narrow angular distribution normal to the surface and a translational energy characterized, by a temperature (T=110K) significantly lower than that of the substrate (T=295K).$^{1}$ Atomic oxygen products display both broader angular and kinetic energy distributions than that of the CO fragments. Emission of O($^{3}$P) is seen at angles greater than 30° with respect to the surface normal. In contrast, recent PSD studies of product NO from single crystal sodium nitrate (NaNO$_{3}$) show product distributions with both thermal and hyper-thermal components.$^{2}$ Projected density of state plots computed using periodic Hartree-Fock theory indicate a strong overlap in the metal and carbonate bands of the low lying excited states in CaCO$_{3}$, while NaNO$_{3}$ was found to have a well-separated nitrate band in the excited state below the mixed metal/nitrate bands. The differences in the electronic structure of these materials may account for differences in the observed product distributions in the PSD of calcite and sodium nitrate.
ISSN 03615235
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 1997-01-01
Publisher Place New York
e-ISSN 1543186X
Journal Journal of Electronic Materials
Volume Number 26
Issue Number 11
Page Count 7
Starting Page 1335
Ending Page 1341

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Source: SpringerLink