NMR in (all) chemical exchange situations
General situation: both signals observable , no supression
Consider: we follow the FID for 0.1 - 1 sec, our spectral width (sw/2) is about 2000 - 3000 Hz, and the minimum sampling rate is 2 /Hz (Nyquist theorem) to separate frequencies:
Exchange rarely happens during FID intermediate(back and forth) Any nucleus switches resonance separate species, separate resonances =no accurate sin = broad line frequency several times in 1 fid
again “exchange broadening” (population)average between two.
Slow exchange intermediate exchange fast exchange