Tb-doped Materials for Visible Lasers

The majority of the fabricated procedures of lanthanide doped materials involve in thermal treatment which often results in crystallite regrowth, stabilizing the specific crystal structure and luminescence enhancement. The efficiency...

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Controlling the Reactivity of C60: A Theoretical Analysis of the Electronic States Modulated by Substitutional Chemistry

MRS Proceedings ◽

10.1557/proc-359-211 ◽

1994 ◽

Vol 359 ◽

Author(s):

S.-H. Wang ◽

M. Kashani ◽

S. Jansen

Keyword(s):

High Temperature ◽

Theoretical Analysis ◽

High Temperature Superconductivity ◽

Electronic States ◽

Experimental Investigations ◽

Cluster Stability ◽

Simple Substitution ◽

Doped Materials ◽

Multiple Species

ABSTRACTThe availability of large amounts of Buckminsterfullerene has allowed a plethora of experimental investigations on fullerenes. The chemical and physical studies have focussed on synthesis, isomerism, magnetism, spectroscopy and high temperature superconductivity in doped materials. The chemical reactivities of fullerenes have been defined and most of the studies are dominated by C60 isomers. Some of the observed activities of fullerenes parlled those of alkeies. In our previous studies, the reactivity of the 6-6' bond with respect to eco- addition was described. Current studies have exploited the olefinic nature of the 6-6' bond and analyzed the effect of the addition on cluster stability and frontier character. In this work, we describe the mechanisms of simple substitution and analyze stability and orbital effects for the addition chemistry of C60 with multiple species. Evolving changes in orbital frontier character are analyzed with respect to site directed chemistry exhibited by C60.

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Characterisation of K-doped Bi4V2O11 by combined XRD and EPMA: A cautionary tale

Powder Diffraction ◽

10.1017/s0885715600009829 ◽

1997 ◽

Vol 12 (4) ◽

pp. 245-247 ◽

Cited By ~ 1

Author(s):

C. K. Lee ◽

A. M. Coats ◽

A. R. West

Keyword(s):

Powder Diffraction ◽

Electron Probe ◽

Solid Electrolytes ◽

Single Phase ◽

Variable Composition ◽

Cautionary Tale ◽

Phase Purity ◽

X Ray ◽

Phase Pure ◽

Doped Materials

A comparison of X-ray powder diffraction and electron probe microanalyses on samples of Na- and K-doped Bi4V2O11 (BIMEVOX) solid electrolytes indicates some of the problems associated with using XRD to assess phase purity, especially in materials of variable composition such as BIMEVOXes. In this study both the Na- and K-doped materials appeared phase pure by XRD. EPMA indicated the Na-doped materials to be single phase with their expected compositions while the K-containing materials were not phase pure with very little K present in the main BIMEVOX phase.

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