NMR Flashcards
What is NMR
Nuclear Magnetic Resonance Spectroscopy
What atoms behave if they are spinning
Hydrogen
Carbon
Nitrogen
Fluorine
Why do atoms spin
They possess a magnetic moment so the nuclei behave as little magnets
What happens to the spin state when there is a lack of external influence
The spin state adopted by the nucleus is of the lowest energy state
What happens to the spins of a nuclei when in a magnetic field
the spins precess their alignment, meaning it rotates on an axis different from its alignment.
When removed from a magnetic field what occurs to the precessed spin states
they return back to their preferred spin state
What are the 3 main things is NMR used for
Used to gain information about
- 3d structure of molecules
- topology of molecules
- dynamic behavior in solid state
Describe the two alignment state that a hydrogen nucleus can have in an external magnetic field
Aligned
or
Opposed
By supplying energy to the nuclei what happens to its alignment
By providing the correct amount of energy the alignment can flip from stable to unstable.
What is the preferred state known as
Ground State
What is the unstable state known as
Excited State
What is relaxation
Processes by which an excited magnetic state returns to its equilibrium distribution
What measures Relaxation
Rf detector
What is the output detected by the Rf detector
Hint* FID
Free inductive decay
What is resonance condition
flipping of the proton from one magnetic alignment to the other by radio waves
