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Visualising Nuclear Magnetic Resonance by Erik Kountz


This semester I was involved in research with Professor Giannetta who specializes in nuclear magnetic resonance. We do not do a lot of visualization of how nuclear magnetic resonance, or NMR, works on an atomic scale. At times this is a problem, because nuclear magnetic resonance is not the most intuitive concept to understand, so my project for this class was to model the magnetic dipole moments of hydrogen and carbon nuclei in an external magnetic field. In particular, I simulated the simpler technique of constant wave NMR.

  1. Here is an image of my program once it opens. The circles represent different elements, black for carbon and yellow for hydrogen.

  2. The NMR machine displays a graph of frequency absorbed versus frequency. Because carbon atoms absorb at a smaller frequency, the number of carbon atoms that flipped will be on the left and the number of hydrogen atoms that flipped will be on the right side. The reason the lines representing the frequency absorbed are so thin is because an element will only absorb a very specific frequency of radio wave. If the graph was drawn to scale, the lines would be so narrow that they could not be displayed or seen.

  3. Here the radio waves passed horizontally across the sample. Now all atoms are in a high energy state and the NMR machine counted the number of carbon and hydrogen atoms that flipped for each row.

  4. Now that this has happened, we are ready to repeat the previous procedure.

  5. We now see the same the graphs for each column displayed. As no radio waves went in the horizontal direction, the row graphs are blank. The bars that remain show the high count for the number of carbon and hydrogen atoms that have been flipped in past tests.

  6. This is our final result. The graphs now show the number of carbon and hydrogen atoms in each row and column.

  7. We are now ready to preform constant wave NMR for a new sample.