Proton spin system in pentacene and its interaction with photoexcited triplet electron spin

Reading of single spin states is the main experimental problem in quantum computing. Pentacene is one of a few molecules on which the optical read‐out of single spin experiments were performed. The shape of optical single molecule spectroscopy (ODMR) signal depends on an interaction of triplet state of two unpaired electron spins with proton bath. These protons form a Heisenberg chain with N = 14 nodes. We investigate the symmetry of this system in selected inversed spin sectors of 214 nuclear spin configurations. In particular all exact Bethe solutions for two reversed spins have been derived. The interaction of electron and proton spin systems has been addressed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)