Set 6 – Classical Description
- Page ID
- 79281
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- What happens when an electrical current is run through a wire coil?
- What happens to the nucleus after B1 is turned off?
- Suppose a wire coil is placed on the Y-axis.What happens in the wire coil as the magnetic field of the tipped nucleus is imparted on it?
- Draw the current profile that would result in the wire coil on the X-axis as the tipped nucleus relaxes back to its ground state.
- Draw the FID that would result if the nucleus had a much shorter relaxation time.
- Do you see a problem with performing a FT on an FID with a very short relaxation time?If so, what would happen in the resulting frequency domain spectrum?
- Where is the amplitude of peaks determined in the FID?
- Why is a delay time incorporated into the sequence?
- Why are the advantages and disadvantages of using 30o pulses instead of 90o pulses?
- What is the advantage of recording several FIDs and adding them together?
- Suppose the following pulse sequence is used to obtain the spectrum of a 13C nucleus with a spin-lattice relaxation time of 100 seconds (90o pulse, 1 second collection of the FID, 1 second delay).Note, carbon atoms with no directly bonded hydrogen atoms can have relaxation times as long as 100 seconds.This pulse sequence is repeated four times.
- Draw the position of the 13C magnetization vector after each of the four pulses.
- Draw the corresponding FID that would be obtained after each pulse.
- Draw the composite FID obtained by adding the four individual FIDs together.
- What do you observe for this carbon in the resulting frequency domain spectrum?