181* NMR pulse, atomic description

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    Atomic Nmr Pulse
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SUMMARY

The discussion focuses on the intricacies of a 181* NMR pulse, emphasizing the limitations of conventional explanations that primarily address 180* pulses. Participants highlight the need for a detailed spin-by-spin analysis to fully understand the mechanism behind a 181* pulse, as traditional explanations often resort to bulk responses. The conversation critiques the adequacy of existing explanations and encourages deeper exploration into the atomic-level interactions involved in NMR pulse sequences.

PREREQUISITES
  • Understanding of NMR (Nuclear Magnetic Resonance) principles
  • Familiarity with spin dynamics and magnetic resonance phenomena
  • Knowledge of RF (Radio Frequency) energy application in NMR
  • Basic grasp of bulk magnetization concepts in NMR
NEXT STEPS
  • Research the mechanics of spin-by-spin interactions in NMR
  • Explore advanced NMR pulse sequences beyond 180* pulses
  • Study the role of RF energy in manipulating spin states
  • Investigate the concept of bulk magnetization in detail
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Physicists, chemists, and researchers involved in NMR spectroscopy, as well as students seeking a deeper understanding of atomic-level interactions in magnetic resonance applications.

dilberto
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Hi, long time user, first time poster.

A while back someone posted a great question
https://www.physicsforums.com/showthread.php?t=33584

To paraphrase, can you explain on a spin-by-spin level exactly how a 181* pulse is possible?

You always hear this really intuitive explanation of NMR pulses as a net imbalance of low energy state spins and as you excite them with RF energy, they go to high energy state. This causes the net imbalance to tip from 0*, to 180*. However, this explanation seems to only describe up to 180* pulses. The answers from 2004 trend towards bulk response and arm waving as soon as the questioner really presses on a 181* pulse.

So what's going on? Is the common explanation actually lacking in completeness. This seems like such a great little thought experiment. Thanks for any insight.
 
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I don't think it was "arm waving" at all, considering the medium that one has to use to do such explanation (public forum). I thought the last 2 explanations by clint and Mike H was quite detailed. They tried to explain what is meant by the bulk magnetization, which is what we measure.

For a "long time user" (you officially joined yesterday), you had to dig up a very old thread to make your first post?

Zz.
 

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