Electron Distributions in Pure Selenium and Tellurium and with Tellurium and Selenium Impurities 77Se and 125Te Nuclear Quadrupole Interactions.

Hwa-Suck Choa, J. H. Parka and T. P. Dasb *

a  Department of Physics, Yeungnam University, Kyungsan, 712-749, Korea
b  Department Physics, State University of New York at Albany, Albany, NY, 12222, USA

*  Corresponding Author: FAX 1-(518)-442-5260

Using the Hartree-Fock cluster procedure, we have studied the electric field gradient tensors at the nuclear sites of 77Se and 125Te in both selenium and tellurium crystalline systems. From the results for 77Se in selenium and 125Te in tellurium, using the observed quadrupole coupling constants, we have determined the values of the quadrupole moments Q (77Se)=0.74±0.07 barns and Q (125Te)=0.35±0.04 barns. Comparison will be made with earlier values obtained by different methods. Our calculated values of Q and the theoretical field-gradient tensors for 77Se in tellurium and 125Te in selenium lead to quadrupole coupling constants in agreement with experiment within about 15 percent, the calculated asymmetry parameter for 77Se in tellurium also being in reasonable agreement with experiment. Experimental measurement of the asymmetry parameter of 125Te in selenium to compare with theory is needed.

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