We have studied the excited triplet states of [2.21-and [3.31 paracycIophane by emission spectroscopy and by ODMR and have compared the results with the corresponding monomer para xylene. The most striking result is that both phanes exhibit two sets of zero field splitting parameters indicating the existence of two nearly degenerate low lying excited triplet states. Furthermore, we fmd in distinction to expection a stronger reduction of the zero field splitting parameters as compared to the monomers for [3.3 J paracyclophane than for [2.2 Jparacyclophane. The causes of these surprising experimental findings are discussed.

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