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I am asking this question after asking a similar one for spontaneous nuclear decay phy.stack. Link

Order of reaction is defined for chemical reaction. But wikipedia says about spontaneous nuclear decay:

Another class of first-order reactions is radioactive decay processes which are all first order. These are, however, nuclear reactions rather than chemical reactions.

Spontaneous nuclear decay is governed by nuclear forces for which it follows an exponential form. There can be deviations from the exponential law at very short time and at very time. But, that's under nuclear physics.

But, has anyone tried to extend the concept of order of reaction to other nuclear reactions eg. transmutation, spallation,fission,fusion etc.

Ben Crowell's comment on my previous phy.stack post:

If you want to make an analogy with chemical reactions, then you should probably be considering nuclear reactions, rather than spontaneous nuclear decay. For example, you could consider the cross-section for neutron or proton transfer reactions as a function of the number of nucleons (mass number) in the target and projectile.

Wikipedia page on nuclear reaction says on rate of nuclear reaction:

If the reaction equation is balanced, that does not mean that the reaction really occurs. The rate at which reactions occur depends on the particle energy, the particle flux and the reaction cross section.

Question: Has anyone tried to define order of reactions for nuclear reaction? Even though concept of order of reactions might not be that useful for nuclear reactions, has anyone modified it to work with nuclear-chemistry?

P.S. I am not sure if this question is suitable here. If it isn't, then just migrate it phy.stack.

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    $\begingroup$ There is nothing to extend or modify; the ordinary definition applies just fine. Most nuclear reactions (except fusion) would be first order. $\endgroup$ – Ivan Neretin Jul 10 '17 at 5:59
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    $\begingroup$ @IvanNeretin Exactly. It is not the nature of the process that is important when it comes to kinetics description, but rather how many particles participate in a single act of this process. Probably it somewhat bothers people because they are used to render reaction order as concentration's exponent. $\endgroup$ – andselisk Jul 10 '17 at 6:28
  • $\begingroup$ @Ivan Neretin Why fusion isn't first order too? $\endgroup$ – Mockingbird Jul 10 '17 at 6:44
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    $\begingroup$ Because it includes two particles reacting, or maybe even more. $\endgroup$ – Ivan Neretin Jul 10 '17 at 7:06
  • $\begingroup$ What about fission? $\endgroup$ – Mockingbird Jul 10 '17 at 11:40

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