Temperature dependent optical spectroscopy: A study of holmium diphenanthroline nitrate in DMF

Abstract A detailed spectroscopic study of the optical properties of Ho(phen)2(NO3)3 complex is presented. The substance is characterized by UV/Vis spectroscopy, IR – spectroscopy, chemical analysis and X – Ray diffraction. Temperature dependent absorption spectra of Ho(phen)2(NO3)3 in DMF are discussed. A hyperchromic effect at elevated temperatures of the electric dipole absorption transition 5I8→5G6 at 452 nm is observed and a quantitative explanation in the framework of the coth(x) theory of absorption line broadening is suggested. The thermal depopulation of the 5I8 electronic level also is discussed.