A study of solvent effects on mechanical anharmonicity of vsub(1) vibrations in D-chloroform

Frequencies of the fundamental C-D stretching band and its first and second overtones were measured for D-chloroform. The conclusion of Buckingham's theory, namely the linear proportionality of solvent effects to the vibrational quantum number, was verified. The results indicate that Buckingham's theory, using a second-order perturbation technique, is not satisfactory in describing the obtained regularities. For this reason, the improved vibrational terms of Rossi, Nguyen-Van-Thank, Brodbeck and Haeusler were used to calculate anharmonicity constants. Anharmonicity constants were found to be solvent dependent. The results of D-chloroform and chloroform were used to discuss isotopic effects on solvent shifts. (author)