Principles of resonance absorption

3 y-RESONANCE (MOSSBAUER) SPECTROSCOPY 8.3.1 Principles of resonance absorption 

In certain circumstances, a snbstance is capable of absorbing electromagnetic energy, particularly, powerfully and selectively. This happens when the energy of a falling quantum coincides with the electron and/or nnclear energy level difference. Then, so-called reso-mnce absorption of the electromagnetic radiation occurs. 

Suppose that the sample contain atoms with two intrinsic energy levels and o- The resonance condition can be written as  

The resonance curve is characterized by several parameters position, width on half of the height (half-width) and intensity (height of maximum or absorption depth ). 

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