The Vibrational Stark Shifts of Sulfate Internal Modes in SO42- Doped Potassium, Rubidium and Cesium Selenates. A Quantum Model for Measurement of Crystalline FieldsReportar como inadecuado




The Vibrational Stark Shifts of Sulfate Internal Modes in SO42- Doped Potassium, Rubidium and Cesium Selenates. A Quantum Model for Measurement of Crystalline Fields - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Croatica Chemica Acta, Vol.73 No.4 December 2000. -

A quantum theoretical basis for the experimentally observed vibrational Stark shifts of the sulfate internal modes in SO42- doped K2SeO4, Rb2SeO4 and Cs2SeO4 is presented. Analytical first order perturbation theoretical expressions are derived for the field-dependent wavenumbers of the 1 ← 0 and 2 ← 0 transitions, harmonic wavenumbers, as well as for the Stark tuning rate and the electrostatic field strength at the Cs sites of the host lattices. It is shown that the local field differences are the factor dominating over the differences in the anharmonicities of the guest anions in various host lattices, and are thus responsible for the experimentally observed trends. The proposed method allows calculation of the local crystalline field strength if the anharmonic potential energy parameters of the dopant anions are known. The calculated values for the studied series of matrices range from 229 to 259 V nm-1, which are approximately 3 times larger than those reported for water molecule sites in several clathrate hydrates and for the N2O adsorbed in the NaA zeolite cavities. The model also successfully explains the greater bond length distortions than the angular ones of the dopant anions observed in ali studied cases.

vibrational Stark effect; perturbation theory; sulfate impurities; internal crystalline fields; solid Solutions; isomorphous isolation; mixed crystals



Autor: Ljupčo Pejov - ; Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Cyril and Methodius University, P. O. Box.

Fuente: http://hrcak.srce.hr/



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