Question

Explain the source of an FID signal in FT-NMR

Short answer

Free induction decay (FID) is the detectable NMR signal generated by non-equilibrium nuclear spin magnetization precessing about the magnetic field in Fourier transform nuclear magnetic resonance spectroscopy.

Step-by-step solution

Definition of FID signal in FT-NMR.

In FT-NMR, a radio frequency pulse is used to irradiate all frequencies in a spectrum at the same time. The nuclei revert to thermal equilibrium after the pulse. As the nuclei relax, the device records a time domain emission signal.

Consider an example.

Consider the case of a compound's nucleus being exposed to a strong magnetic field in pulsed NMR experiments, as well as very brief pulses of intense RF radiation.

Explain about RF Radiation

Each pulse is a packet of RF radiation, which in turn consists of many more cycles.