Lattice vibrational dynamics of nanostructured CdO lattice with two slightly different lattice constants (4.69 and 4.61 Å) has been investigated using Born von Karman model. CdO materials were prepared as thin film form on glass substrate by spray pyrolysis technique. An aqueous solution of 0.05 M Cadmium acetate is sprayed as fine mist on the preheated glass substrate at two different temperatures to form CdO thin film. The CdO films obtained at 220°C and 260°C have lattice constants of 4.69 and 4.61 Å, respectively. Born von Karman model was employed to obtain the dispersion relations of phonons and frequency density of states of the face centered cubic structured CdO crystals. Born Mayer potential was used to estimate the force constants of inter-atomic interactions between first five neighbors for both the CdO lattices. The dynamical matrix was constructed with the estimated force constants and hence eigen values and vectors were determined for a set of 73 wave vector points obtained from reciprocal lattice. The density of phonon states found to be accumulated in the higher frequency region. The amplitude of lattice vibration that is Debye Waller factor and lattice contribution to the specific heat capacity was estimated for various temperatures. A significant change in phonon dispersion, specific heat capacity and Debye Waller factor values have been observed between the nanostructured CdO crystals of different lattice constants.
Lakshmi Narasimha Acharya Kandala, John Bosco Balaguru Rayappan, Jeyaprakash Beri Gopalakrishnan, Stalin Mano Gibson Manasai and Lawrence Nallathambi, 2012. Effect of Least Variations in the Lattice Constant in the Lattice Dynamics of Nanostructured CdO. Journal of Applied Sciences, 12: 1726-1729.