I think it might depend on the trap? You have several traps corresponding to several energy levels. Can you specify the publications where this was discussed?

To the best of my knowledge, in stimulated luminescence, for OTOR model, during stimulation re-trapping is never greater than recombination. But if we study fading in a more systematic manner, it is usually observed that the low temperature peak fades more quickly than the high temperature peak. Sometimes, the intensity of some high temperature peak found to increase in expense of the low temperature peak with time. I think, at this stage, the recombination of the charge from the shallow trap is less than the re-trapping at some deep trap. However, this process is athermal.   

In CW-OSL, if the OSL signal shows a peak instead of just a normal decay as is expected of CW-OSL, it is an indication that there is more retrapping than recombination at the beginning of the read-out. In TL however, it is tricky to tell if retrapping is exceeding  recombination.

Thanks to all the researcher who have commented but the fact is that retrapping can never be greater than recombination probability.

If u see one trap and one recombination model otor model. Various possibilities exist. There Am is called retrapping coefficient I.e. sigma x velocity. Retrapping coefficient can be more than Recombination coefficient but other factors like dose etc. R present. See Chen Sirs books and papers. It's possible.

Dear Munish wait for sometime I will clarify your doubt mathematically. I will not use some wild assumption where anything is possible. The paper is in progress.

Dear Dr Singh see theory may predict. The question is experimental observation. It's not so straight in experiments. In theory take possible logical values of doses and sigma and velocity. See how otor model behaves. U may take Am/An  from .001 to 1000. Doses from 10^15 to 10^23 per m^-3. In practice neighbouring traps also play competing roles to further affect the tl glow curves. 

Even heating rate dependence changes need to be included. See in laser heating people has gone up to few thousand degree per second and quasi equilibrium leads delay .

I will be very happy to see new model and it's predictions. 

Please note in theory wider possibilities can be considered but they must be logical.

I agree with Dr Kumar that in theory, we can consider some extreme conditions, some of which are practically impossible to achieve.

I feel the question "can re-trapping greater than recombination be possible? " needs to be clear about what point of view we are looking. Is it during stimulation stage or in storage after irradiation? As I added in my previous comment, for some material re-trapping can be higher than recombination during storage. I can show the proof for Al2O3:C. The paper is accepted and now in press. I will update once it available.

I will be happy to see the paper of L.L. Shing as well.

Dear Dr. Jitu and Dr. Munish as I have said previously just wait I will show it to you,  why retrapping cannot be greater than recombination. You are viewing the parameter from the wrong angle.

Im waiting both paper...  

Dear Dr. Jitu and Dr. Munish kindly see this paper (http://dx.doi.org/10.1080/10420150.2017.1303836) it  will help you why retrapping can't be greater than recombination

http://dx.doi.org/10.1080/10420150.2017.1303836

First of all, congratulation…! I read your paper and well understood the content… well done...!

Now I have a few comments to add…

If you look carefully to my both answers (24 Aug, 2016 and 16 Mar 2017), you must see that I said in some materials, during STORAGE re-trapping can be greater than recombination. But,  if we consider OTOR model, DURING STIMULATION, it’s not possible. So, my both answers hold good...

What I said is if you keep an irradiated material in dark, you may see that the intensity of some low temperature peaks decrease with time whereas the intensity of some high temperature peaks increase. I said, DURING THAT TIME the re-trapping of electrons at the traps corresponding to the high temperature peaks is higher than the recombination of electrons escaped from those traps. Therefore, we may see the increase of intensity of the high temperature peaks.

I never find any theoretical model that explained the reverse fading behavior. If you have please share the link…

The main problem is to interpret the experimental results. For example, according to theory, at room temperature, the TL peaks at temperature, say, above 120 oC should not fade at all. But practically they fade. Now let’s suppose someone develops a theory that explains why the 120 oC peak of say XX material fades at room temperature. If you try to apply the same theory for some different material, say YY, you may see that the theory does not hold good…That’s way we need to experimentally study the results of individual materials.

Lastly, thank you for sharing your paper..!

Deat Dr. Jitu read the paper carefully

Dear Dr. Singh,

I think you are not following what I mean.

Let me differentiate two things carefully: In your paper, you discussed all the things "during stimulation". But, please think the condition during storage (i.e., during fading) where we do not stimulate the sample but still the electrons escape from the traps. My all comments are on fading NOT DURING STIMULATION. Please don’t confuse…!

read my paper derivation of an expression for lifetime in OTOR model