T H FREEDA and C MAHADEVAN

 Department of Physics, S.T. Hindu College, Nagercoil 629 002, India

Pure and impurity added (with NH₄ Cl, NH₄NO₃, NH₄H₂PO₄, and (NH₄)₂SO₄) KDP single crystals were grown by the gel method using silica gels. X-ray diffraction data were collected for powder samples and used for the estimation of lattice variation and thermal parameters like Debye--Waller factor, mean-square amplitude of vibration, Debye temperature and Debye frequency. The thermal parameters do not vary in a particular order with respect to impurity concentration. The results obtained are reported and discussed.

Keywords:  Impurity added KDP crystals; gel method; x-ray diffraction analysis; lattice parameters; Debye--Waller factors; Debye temperatures; Debye frequencies.

Pacs Nos.  61.10; 63.70