NMR Theory and Relaxation

Question 1

spin 0 has population _____ and ___ coherence

Answer 1

alpha over populated
no signal

Question 2

spin 90 has population _____ and ___ coherence

Answer 2

alpha is equal to beta
+ signal

Question 3

spin 180 has population _____ and ___ coherence

Answer 3

beta over populated
no signal

Question 4

spin 270 has population _____ and ___ coherence

Answer 4

alpha is equal to beta
- signal

Question 5

spin 360 has population _____ and ___ coherence

Answer 5

alpha over populated
no signal

Question 6

Define Relaxation

Answer 6

Generally, after a pulse we are no longer at ground state

Question 7

T1 (half-life)

Answer 7

Longitudinal relaxation. Z axis. Quantifies rate and energy transfer.
A measure of how quickly the net magnetization vector will recover to its ground state. Depends on other spins, Usually takes longer than T2

Question 8

T2 (half-life)

Answer 8

Transverse relaxation (spin-spin). Quantifies rate of magnitudinal decay on XY plane. Loss coherence, biggest factor is field inhomogeneity.