We are in process of designing an NMR experiment for our physics lab. The equipment has been set and we obtained resonance frequency for some samples. The setup is a bit rudimentary with a very small frequency range available (16 to 22 MHz). Now I know we can do a bunch of things with a NMR signal with regards to sample detection and analyzing the nature of the compound but that would take it more towards chemistry or physical chemistry. I want to keep it more towards physics. So, I have two queries in this regards:
When we obtained the signal on an oscilloscope (picture attached), in the XY mode, the x axis port comes from the magnetic field and it appears that it is the strength of the oscillating magnetic field.The Y axis in the oscilloscope comes from the NMR probe. But I can't seem to find what the NMR probe actually measures. The output must be voltage as a function of that signal but I cant understand what is it measuring. In an ESR (electron spin resonance) setup for example I have seen that when the resonance frequency is set the loss of energy from the oscillating field causes the impedance of the field to change and that is what is being measured. Is it the same for NMR?
In an ESR if you use DPPH (DiPhenyl Picryl Hydrazyl) as a sample and measure the gyromagnetic ratio of the electron, since there is only one unpaired electron in the entire molecule the g-factor of the electron comes out to be very close to that of a free electron. I was wondering, is it possible to find a compound where there is only a free proton (primarily) and if that compound could be used to measure the approximate g-factor of a free proton just like in the case of ESR of DPPH? And if yes, then which material is recommended?