4
$\begingroup$

I'm having some trouble rationalizing why nuclei with low gyromagnetic ratios are considered unreceptive in NMR. I know it's because it will take a higher magnetic field to "hit" its Larmor Frequency (putting aside more advanced techniques like cross-polarization or DNP), but what physical significance does the value have in NMR beyond that? I know it's a ratio of magnetic moment to angular momentum, so could it have to do with speed of Larmor precession that makes it unreceptive, or maybe a smaller population difference due to small spacing between energy levels?

For instance, comparing 103Rh to 1H, both are almost 100% abundant (103Rh is slightly more abundant, in fact), but 1H is enormously more receptive than 103Rh, which I can only attribute to the difference in gyromagnetic ratios since they're both spin-1/2 and don't have a quadrupole moment.

I'd appreciate any direction you could offer!

$\endgroup$
2
  • 1
    $\begingroup$ The SNR varies as $\gamma^{11/4}$, which is explained further in this question & its answers: chemistry.stackexchange.com/questions/131689 $\endgroup$ Apr 25, 2022 at 0:28
  • 2
    $\begingroup$ [For 103Rh specifically, there is another complicating factor in that you need to make sure that you have a probe that can go to such low frequencies... many probes out there only go down to 15N which is still ~3x higher frequency than 103Rh.] $\endgroup$ Apr 25, 2022 at 1:17

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.