Proton Exchange Effects in Laser Photolystic P-Benzosemiquinone Spin Polarized Radicals

The TRESR spectra of benzosemiquinone radical and the ethylene glycoi ketyl radical formed from laser photolysis of P-benzoquinone in ethylene glycoi or ethylene glycol/water systems are presented. The photon exchange between p-benzosemiquinone radicals PBQH⁺ and their protonated forms PBQH⁺ is studied by adding H₂SO₄ to the solution. The experimental results show that different hyperfine lines for PBQH⁺ have different time-dependence which depend upon the fraction of the overall number of nuclear spin states, and that the lines with smaller fraction are decay fast.