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ForgetfulPhysicist
- 31
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NMR textbooks often state that an ensemble of nuclei cannot absorb the excitation radiowaves if the spin population is "saturated" (wherein "saturated" is often described as equal spin population in all energy states, or a population inversion). But these same NMR textbooks show that a 180 degree "flip" of nuclei population can be executed by a pulse of radiowaves, thus causing a population inversion.
My question is: How can a population inversion be created by incoming radiowaves when "saturation" should prohibit the radiowaves from being absorbed by the nuclei once the spin population is equalized?
My question is: How can a population inversion be created by incoming radiowaves when "saturation" should prohibit the radiowaves from being absorbed by the nuclei once the spin population is equalized?