Knowledge Bank

The Rashba effect is discussed with particular reference to triplet state exciton bandstructures. As the energy of isotopically substituted guest molecules vary from the deep trap limit to the shallow trap limit, the spin quantization axes of the guest change from a molecular based set to a crystal based set in systems which contain “interchange equivalent” resonance interactions. Carbon-13 molecular impurities are appropriate shallow traps with which to demonstrate this effect and also to expose the bandwidth (symmetry) of vibronic transitions. Some new experimental results on aromatic crystals with known bandstructures illustrate the utility of Carbon-13 trap states to probe bandstructures.