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ChrisVer
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http://en.wikipedia.org/wiki/Mössbauer_effect
I was looking at this article, trying to prepare myself for experimenting this effect. What I understood is that Moessbauer effect explains the reason why you can have gamma absorbtion/emission in solids while you can't for gases.
However at the description it says:
From this I don't understand what's the problem of the recoiling...
You send some gamma on a nucleus, it gets excited and then it emits the extra energy in another gamma and recoiling. Why should we care about the last gamma's energy?
Secondly, what is the reverse transition? If it means that they can be reabsorbed by another nucleus of the same matterial, then it should excite it in the same energy level and not less. Suppose you have a 3MeV ray emitted from the 1st nucleus, it should excite the 2nd to 3 MeV again...and so on...
Finally I don't understand why nuclei have fixed positions in a crystal and the recoil is taking place for the crystal as a whole. Couldn't they be recoiled but nothing happen to the crystal? like for example cause some oscillations within it. As far as I know the states [gas to solid] is an atomic thing, so why would it concern the nuclei?
I was looking at this article, trying to prepare myself for experimenting this effect. What I understood is that Moessbauer effect explains the reason why you can have gamma absorbtion/emission in solids while you can't for gases.
However at the description it says:
In a transition of a nucleus from a higher to a lower energy state with accompanying emission of gamma rays, the emission generally causes the nucleus to recoil, and this takes energy from the emitted gamma rays. Thus the gamma rays do not have sufficient energy to excite a target nucleus to be examined. However, Mössbauer discovered that is possible to have transitions in which the recoil is absorbed by a whole crystal in which the emitting nucleus is bound. Under these circumstances, the energy that goes into the recoil is a negligible portion of the energy of the transition. Therefore the emitted gamma rays carry virtually all of the energy liberated by the nuclear transition. The gamma rays thus are able to induce a reverse transition, under similar conditions of negligible recoil, in a target nucleus of the same material as the emitter but in a lower energy state
From this I don't understand what's the problem of the recoiling...
You send some gamma on a nucleus, it gets excited and then it emits the extra energy in another gamma and recoiling. Why should we care about the last gamma's energy?
Secondly, what is the reverse transition? If it means that they can be reabsorbed by another nucleus of the same matterial, then it should excite it in the same energy level and not less. Suppose you have a 3MeV ray emitted from the 1st nucleus, it should excite the 2nd to 3 MeV again...and so on...
Finally I don't understand why nuclei have fixed positions in a crystal and the recoil is taking place for the crystal as a whole. Couldn't they be recoiled but nothing happen to the crystal? like for example cause some oscillations within it. As far as I know the states [gas to solid] is an atomic thing, so why would it concern the nuclei?