Non-linear liquid-state NMR

The development of nuclear magnetic resonance spectroscopy for probing liquid-state systems primary results from its ability to exactly predict the evolution of the spin systems even under the influence of very complex pulse sequences. This remarkable feature of liquid-state NMR results from the linear time-domain evolution of the magnetization of a unique spin or more generally of the density matrix of a given molecule. This remarkable feature of liquid-state NMR results from the linear time-domain evolution of the magnetization of a unique spin or more generally of the density matrix of a given molecule. Radiation damping has been known from the early days of NMR. This non-linear interaction being mediated by the detecting coil, strongly depends on its coupling to the precessing magnetization. It is also dependent on the resonance frequency of the electronic circuit. The presence of RD can alter the signal resonance frequency, can forbid the magnetization inversion or can allow the detection of nuclear spin-noise.