AN IR STUDY ON THE STABILITY OF Y(DPM)3, BA(DPM)2 AND CU(CPM)2 FOR UV IRRADIATION

Ultraviolet-irradiation effects at 3 approximately 8 eV (400 approximately 150 nm) have been studied for Y(DPM)3, Ba(DPM)2 and Cu (DPM)2 (DPM: dipivaloylmethane) metalorganic chelates which are commonly used for YBa2CuO7-x superconducting-film formation by metalorganic chemical vapor deposition (MOCVD). An IR spectral analysis shows that the chelate ring of Ba(DPM)2 is most senstively affected when irradiated in a 200 approximately 300 nm region through a pi-pi* transition of the ligand orbital, and Y(DPM)3 shows a similar, but much more modest reaction. On the contrary, Cu(DPM)2 is very stable for all the light sources used. Such a difference of stability is deeply related to the metal-oxygen bonding nature of these chelates.