Singlet-Triplet Absorption Bands in Some Halogen Substituted Aromatic Compounds

Abstract
Singlet‐triplet absorption bands are reported for a number of halogen benzenes and naphthalenes. Combining the results with other data, the rates of radiationless triplet to ground state transitions are found. The effect of the atomic number of a substituted halogen atom on the absorption strength is shown to agree with a simple theory. It is also shown that the spectroscopic moments of substituents do not add vectorially for singlet‐triplet transitions.
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