The NOESY Experiment

Question 1

Pulse sequence

Answer 1

90° (y) -> t1 (Evolution) = 2nd dimension -> 90° (-y) -> theta m (cross peaks) = mixing time -> 90° (y) (transversal Magnetisierung) -> t2 (Detection)

Question 2

Spin Echo

Answer 2

90° -> tau -> 180° -> tau -> detection

Question 3

Free precession 90° Puls

Answer 3

cos 90° = 0
sin 90° = 1
cos 180° = -1
sin 180° = 0

Question 4

Two spins -> all observable

Answer 4

Sx, Sy, Sz, Ix, Iy, Iz

Question 5

Two spins -> double Quanten (not observable)

Answer 5

2IxSx, 2IxSy, 2IySx, 2IySy

Question 6

Two spins -> zero quantum

Answer 6

2IzSz

Question 7

Two spins -> anti phase (observable)

Answer 7

2IxSz, 2IySz, 2IzSx, 2IzSy

Question 8

Anti-phase terms

Answer 8

The anti-phase term that develops during acquisition does not lead to any signal components.
In terms of the product operator formalism anti-phase magnetisation is not observable.
Nevertheless, anti-phase term are commonly observed in NMR spectra, when they develop into in-phase signals.