Luminescence decay curves from one dimensional mixed crystals of CsMn$\sb{\rm x}$ (Mg or Cd)$\sb{\rm 1-x}$Br$\sb3$ with small fraction of Mn (x = 0.02 $\sim$ 0.3) have been analyzed to gain insight into the energy migration. As the temperature is raised, exciton migration between pairs and single ions is observed. Information about exciton migration process between pairs and single ions was obtained by analyzing the kinetics of decay curves obtained at different excitation wavelength. By varying the concentration of Mn$\sp{2+}$ ions, it is possible to determine the critical limit for exciton migration in lattice. Luminescence decays of (CH$\sb3$)$\sb4$NMnCl$\sb3$ doped with Cu$\sp{2+}$ and/or Cd$\sp{2+}$ were measured at various temperatures. By using the HRM model to simulate data, detailed insight into the rates and energy barriers of the different exciton migration processes were obtained The luminescence studies on dimeric d$\sp8$-d$\sp8$ complex K$\sb{4}\{$Pt$\sb2$(PCP)$\sb4\}\cdot$6H$\sb2$O (PCP = $\mu$-P,P,-HO(O)PCH$\sb2$P(O)OH$\sp{2-}$) have been conducted. At room temperature in aqueous solution, the $\sp3$A$\sb{\rm 2u}$ excited state of Pt$\sb2$(PCP)$\sb4\sp{4-}$ has a lifetime of only 0.055 $\mu$s. Measurements of the lifetimes of the excited states of Pt$\sb2$(PCP)$\sb4\sp{4-}$ at various pH and solvent viscosity values were carried out. Small shifts in absorption and emission maxima were observed between the solid and fluid solutions. The activation energy for the nonradiative decay is 1200 $\pm$ 100 cm$\sp{-1}$. The short lifetime of $\sp3$A$\sb{\rm 2u}$ state in solution is likely due to the presence of a manifold of twisted excited state rotamers. The phosphorescent lifetime of the compound shows a temperature dependence that is consistent with a zero field splitting of 39 cm$\sp{-1}$ in the triplet manifold of excited states The unique dimeric Rh complex $\{$Rh$\sb2$(PNP)$\sb4\}$((C$\sb6$H$\sb5$)$\sb4$B)$\sb2$ (PNP = CH$\sb3$N(P(OCH$\sb3$)$\sb2$)$\sb2$) is rather flexible and adopts a number of distinct conformational forms in solid state. Luminescence spectra and emission dynamics of two crystalline forms of the complex show a dramatic temperature dependence which is consistent with a thermally activated structural transformation of the phosphorescent excited state The X-ray diffraction data of the d$\sp8$-d$\sp6$ complexes MM$\sp\prime$D$\sb2$(CO)$\sb4$Cl where M = Rh(I) or Ir(I) and M$\sp\prime$ = Mo(0) or W(0), D = bidentate ligand (CH$\sb3$NP(OC$\sb3$H$\sb7$)$\sb2$)$\sb2$ indicated the presence of a metal-metal bond. The absorption and emission spectra were used to assign the electronic structure. Luminescence lifetimes for this novel type of d$\sp8$-d$\sp6$ dimer were also obtained / acase@tulane.edu
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_27119 |
| Date | January 1990 |
| Contributors | Waguespack, Yan Yin (Author), McPherson, Gary L (Thesis advisor) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Rights | Access requires a license to the Dissertations and Theses (ProQuest) database., Copyright is in accordance with U.S. Copyright law |
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