Abebe, Ayele2018-06-192023-11-092018-06-192023-11-091992-06http://10.90.10.223:4000/handle/123456789/1579The hindered rotation of the diatomic molecuel Co in solid Ar matrix is discussed by propesing the distortion of the octahedral symmetry of the crystal field of the matrix in the vicinity of the impurity molecule to a lower symmetry, in particular tetrahedral symmetry. The solutions of the Schrodinger equation are obtained in general form using group theory analogous to the well known Devonshire model. Numerical calculations of the energy levels and heat capacity for Co molecules in Ar are made for different strength of the crystal field. Qualitative agreement with experimental data in the temperature range 0.5 - 10K is achieved. Parameters characterizing the hindered rotation of Co molecule in Ar are predictedenThe Hindered rotationThesis