NMR: Basic Experimental Principles
Imagine placing a molecule, for example, CH4, in a magnetic field.
We can probe the energy difference of the alpha- and beta- state of the protons by irradiating them with EM radiation of just the right energy.
In a magnet of 7.05 Tesla, it takes EM radiation of about 300 MHz (radio waves).
So, if we bombard the molecule with 300 MHz radio waves, the protons will absorb that energy and we can measure that absorbance.
In a magnet of 11.75 Tesla, it takes EM radiation of about 500 MHz (stronger magnet means greater energy difference between the α- and β- state of the protons)
