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The 13C nucleus is a spin particle, which means it can orient in two directions

ID: 788603 • Letter: T

Question

The 13C nucleus is a spin particle, which means it can orient  in two directions in  a magnetic field (with the field and against it).  The difference in energy between the two orientations is given by:


Change in E = (0.7058*10^-26 J/T) B


where B is the magnetic field strenbth in Tesla.  In an NMR spectrometer with a 1.45 T field strength, what is the ratio of the population of nuclei oriented opposite the magnetic field with respect to those oriented with the magnetic field at 25 degrees Celcius?

Explanation / Answer

Boltzmann Distribution N?/N? = exp(-?E/kT) where N? and N? are the numbers of nuclei in the ground and excited states respectively; ?E is the energy difference between them, k is the Boltzmann const and T the absolute temp. ?E= (0.705