OSCILLATOR-STRENGTHS AND INTENSITY PARAMETERS OF LN(III) COMPLEXES WITH 12-CROWN-4 AND 15-CROWN-5 ETHERS IN ACETONITRILE (LN=HO AND ER)

The absorption spectra of holmium nitrate and erbium nitrate and the d ifference absorption spectra of their complexes with crown ethers were measured in acetonitrile. The crown ethers used in this study are 12- crown-4 and 15-crown-5. The oscillator strengths for the 4f-->4f multi plet-to-multiplet transitions are empirically determined from the abso rption spectra in combination with the difference spectra. The intensi ty parameters Omega(lambda) (lambda=2, 4, 6) for the systems are also evaluated by applying the Judd-Ofelt theorem to the observed oscillato r strengths. The values of the intensity parameters are compared and d iscussed to investigate the sensitivity of the intensity parameters to the ligand environment.