Thermoluminescence studies on photosynthetic energy conversion. II. Activation energies for three energy storage states associated with Photoreaction II of higher plants

Thermoluminescent glow curves of isolated chloroplasts were analyzed to determine activation energy, frequency factor and lifetime of the three glow peaks associated with Photoreaction II. Peak 1 had an activation energy of 0.8 eV, a frequency factor of 1.5 · 1014/s and a lifetime of 0.02 s. This glow peak appeared to be rather different from peaks 2 and 3, which were quite similar to each other. Peaks 2 and 3 gave activation energies respectively of 0.48 eV and 0.57 eV, frequency factors of 7 · 107/s and 1 · 109/s, and lifetimes of about 1.5 s. A second, less reliable method of analysis gave activation energies of 0.72 eV for peak 1 and 0.44 eV for peak 2. Our values are compared with those obtained by other workers, and the possible metastable states reflected by the three glow peaks are discussed.