A THEORETICAL-STUDY OF CADMIUM ETHYLENEDIAMINE AND CADMIUM AMMONIA EXCIPLEXES - COMPARISON WITH EXPERIMENTS

A quantum-chemical calculation has been made for some complexes of cad mium atoms with ethylenediamine and ammonia by using relativistic effe ctive core potentials. Calculated results show that the luminescences from the two-coordinate or cyclic exciplexes correspond to wavelengths longer than those from the one-coordinate exciplexes, in agreement wi th experimental observations. The difference in their wavelengths is e xplained by the fact that in the two-coordinate exciplexes there is a broadening of the p orbitals of the cadmium atom, to which amines inte ract strongly. There is no substantial change in the bond distance of Cd-N at the minimum potential energy for the above two types of comple xes.