Delayed Ionization of Excited Phenanthrene and Anthracene in Solution

Abstract

The delayed ionization of excited states of phenanthrene and anthracene was observed in tetrahydrofuran solution. The measured photocurrent rose, attained a maximum, and decayed in time very long compared to flash duration. No currents were observable in hexane solution and current response was quenched on admission of O₂ to the tetrahydrofuran solutions. The observed time dependence, dependence on flash intensity, and wavelength dependence are consistent with an interpretation based on ³B₁ excitation via intersystem conversion from excited ¹A₁ and the subsequent interaction of two ³B₁ molecules to yield current carriers.