DETERMINATION OF PEAK PARAMETERS FOR THERMOLUMINESCENCE GLOW CURVES OBTAINED FROM SPINACH THYLAKOID PREPARATIONS, USING MATHEMATICAL-MODELSBASED ON GENERAL ORDER KINETICS

Thermoluminescence (TL) bands obtained from spinach thylakoid preparat ions were analysed by computer-assisted models. The use of mathematica l models, based on the general order kinetics of TL peaks, results in acceptable values of peak parameters such as the activation energy (E) , frequency factor (S), entropy (DELTAS) and free energy of activation (FE). Earlier workers, such as Tatake et al. (Photochem. Photobiol., 33 (1981) 243-250), have reported comparatively higher values of the a ctivation energy and frequency factor for the peaks obtained at higher temperatures, namely peaks IV and V. The model used by them was based on the Randall-Wilkins first-order kinetics theory. De Vault et al. ( Proc. NatL. Acad. Sci. USA, 80 (1983) 983-987; Photosynth. Res., 24 (1 990) 175-181) have attempted to justify the high E and S values by pos tulating temperature-dependent equilibria between two or more carriers acting as traps. However, their postulation results in abnormally hig h values even for lower temperature peaks. Contrary to these results, it was observed that the use of general order kinetics models results in lower E and S values. Thus it is evident that the non-consideration of the retrapping of electrons is the reason for the abnormally large activation energy and frequency factor values observed by earlier wor kers. A comparison of the results reported previously and those obtain ed in this work is presented.