Flynn 1 Physics 518 -quantum Mechanics Iii

The Mössbauer effect was first described by Rudolf Mössbauer in 1957. The effect describes how nuclei can emit or absorb gamma-rays without recoiling under certain circumstances. When a free nuclei emits or absorbs gamma-rays, it recoils as a result of energy and momentum conservation. As a result, if a free nucleus undergoes a transition from an excited state to its ground state by emitting gamma-rays, the energy of the gamma-rays will be slightly less than the energy difference between the nucleus' ground and excited states. Gamma-rays emitted in this fashion will not have enough energy to excite other nuclei of the same isotope from their ground states to the initial excited state of the emitter nucleus. When gamma-ray emission or absorption is accompanied by the recoil of the emitting or absorbing nucleus, the condition of nuclear resonance can not be achieved. However, nuclei bound in a solid or some other form can undergo recoil-free emission and absorption of gamma-rays provided the recoil energy of the nuclei is too small to displace it from its position relative to other nuclei in the system. Under these conditions, the energy carried by the gamma-rays is equal to the energy difference between the excited and ground states of the nuclei and nuclear resonance can be achieved. The Mössbauer effect is the description of recoil-free nuclear resonances. The Mössbauer effect can also be used to study the absorption and emission of gamma-rays in a wide variety of materials, usually by Mössbauer spectroscopy. Mössbauer spectroscopy can provide information on how a material chemically binds with other materials. It can also provide information on the magnetic and electric properties of nuclei. The Mössbauer effect has been used effectively in studying the structure and function of hemoglobin, a protein containing iron atoms that transports blood in the body, among other biologically important molecules.