Cm. Sunta et al., GENERAL-ORDER KINETICS OF THERMOLUMINESCENCE AND ITS PHYSICAL MEANING, Journal of physics. D, Applied physics, 30(8), 1997, pp. 1234-1242
Thermoluminescence glow peaks are calculated numerically for a one-tra
p-one-recombination-centre model using a generalized approach. Except
in extreme cases the peaks are seen to change in position and shape wi
th a change in dose. These glow peaks are fitted to the general-order
kinetics model and the values of the kinetic parameters, namely the ac
tivation energy, pre-exponential factor and order of kinetics are dete
rmined by finding the best fit. In this way an attempt is made to corr
elate the empirical parameters with the physically meaningful ones in
the framework of the adopted model. The fitted value of the activation
energy matches reasonably its input value used in the generalized app
roach model calculations. The fitted values of the order of kinetics a
nd the pre-exponential factor parameters change with the initial occup
ancy of the traps (dose) in all cases in which the order of kinetics (
KO) is found to be in the range in which 1 < KO < 2. The KO decreases
with increasing trap occupancy whereas the pre-exponential factor incr
eases. The latter parameter undergoes a change also in its units. It i
s observed that, when the found value of the KO is such that 1 < KO <
2, the best fitted general-order kinetics peak deviates significantly
from the computed peak. A better fit is found with two peaks, one of w
hich is approximately of first order and the other approximately of se
cond order. The KO parameter at saturation dose has been correlated wi
th the ratio of the re-trapping and recombination cross sections. Thes
e theoretical results are discussed in the perspective of experimental
observations in general. Plausible reasons for disagreements between
theory and experiment are also discussed.