Results of temperature and wavelength dependent fluorescence lifetime and accumulated photonecho experiments on the J aggregate of the dye 5,5Ј,6,6Ј-tetrachloro-1,1Ј-diethyl-3, 3Ј-di͑4-sulfobutyl͒-benzimidazolocarbocyanine ͑TDBC͒ in an ethylene glycol/water glass are reported. Additionally, the temperature dependent relative fluorescence quantum yield was determined. Using two-color pump-probe spectroscopy, the intersite correlation of the frequency disorder and the size of the coherence domains were estimated. Both the phase and the population relaxation times are frequency dependent in the echo and the single-photon-counting experiments. The dependence of the fluorescence lifetime on detection wavelength is restricted to temperatures below 80 K, indicating a temperature activated process. From our experiments and by comparison with previously published results we conclude that the dispersive nature of both the dephasing and the depopulation is caused by intraband relaxation processes. At higher temperatures this wavelength dependence vanishes due to thermalization. The temperature dependence of the relative fluorescence quantum yield of TDBC is equal to the one of pseudoisocyanine ͑PIC͒. Using a motional narrowing model for disordered molecular aggregates with consideration of intersite correlation, at 1.5 K, the two-color pump-probe experiments indicate a very high correlation in the frequency disorder in TDBC J aggregates with a correlation length of several hundred molecules. From pump-probe experiments the delocalization length of the exciton is determined to be between 30 and 45 molecules at 1.5 K.

In molecular photochemistry, charge-transfer emission is well understood and widely exploited. In contrast, luminescent metal-centered transitions only came into focus in recent years. This gave rise to strongly phosphorescent CrIII complexes with a d3 electronic configuration featuring luminescent metal-centered excited states which are characterized by the flip of a single spin. These so-called spin-flip emitters possess unique properties and require different design strategies than traditional charge-transfer phosphors. In this review, we give a brief introduction to ligand field theory as a framework to understand this phenomenon and outline prerequisites for efficient spin-flip emission including ligand field strength, symmetry, intersystem crossing and common deactivation pathways using CrIII complexes as instructive examples. The recent progress and associated challenges of tuning the energies of emissive excited states and of emerging applications of the unique photophysical properties of spin-flip emitters are discussed. Finally, we summarize the current state-of-the-art and challenges of spin-flip emitters beyond CrIII with d2, d3, d4 and d8 electronic configuration, where we mainly cover pseudooctahedral molecular complexes of V, Mo, W, Mn, Re and Ni, and highlight possible future research opportunities. Graphical abstract

Background: The Institute of Medicine, The Joint Commission, and the U.S. Department of Health and Human Services all have recently highlighted the need for cultural competency and provider education on lesbian, gay, bisexual, and transgender (LGBT) health. Forty percent of LGBT patients cite lack of provider education as a barrier to care. Only a few hours of medical school curriculum are devoted toLGBT education, and little is known about LGBT graduate medical education.

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