Radiation damping diagnostics

Radiation damping in modern NMR experiments: Progress and challenges

“…In a notable review article, Szantay and Demeter [37] point out that weak RD effects are seldom detected, although they can appreciably influence the recovery of non-equilibrium magnetization to thermal equilibrium as in relaxation-time measurements. The authors observe that in spin–lattice relaxation time measurements, weak RD does not alter the shape of the recovery curve when a near 180° pulse (inversion recovery) is used.…”

“…However for a near 90° pulse (saturation recovery), the RD effects can appreciably shorten the time to recover to thermal equilibrium even if the RD time ( τ rd ) is an order of magnitude longer than the effective spin–spin relaxation time ( $T_2^{\ast }$). A new experimental scheme, RD difference spectroscopy (RADDSY) was proposed to reveal the effect of weak RD [37]. For high sensitivity probes it is reasonable to assume that these effects might influence magnetization-transfer processes such as found in experiments involving cross-relaxation or chemical exchange and in particular for dynamical events occurring at time scales < $T_2^{\ast }$.…”

“…Since, then articles have appeared describing RD effects on multiplet shape [24], solvent suppression [25], spin–lattice and spin–spin relaxation measurements [26,27], the use of RD to determine chemical exchange rates [28,29], and radiation damping-induced spurious peaks in 2D spectroscopy [30]. Several aspects of the theoretical framework of RD both in homogenous and inhomogeneous fields [31,32] as well as review articles covering many other related aspects of the field have been presented [33–37]. …”

Ultrafast Two‐Dimensional NMR Relaxometry for Investigating Molecular Processes in Real Time

“…[33] In contrast, in the single-scan experiment, the effect of radiation damping is suppressed due to the fact that there is no coherent transverse magnetization during the IR part because of the continuously varying phase of the frequency sweep pulse and the use of a sweep gradient. However, this is not a limiting factor as long as highconcentration samples are investigated using a modern and sensitive, high-field NMR apparatus.…”

Effects of radiation damping on Z-spectra

“…RD has also been observed in hyperpolarized 3 He at 1.5 T, used in imaging of lungs [19]. A good deal of work has been carried out describing inhomogeneous line broadening in the presence of RD using an isochromat model [1,[20][21][22][23], provoking an interesting and significant response [24] regarding the appropriateness of the model in this case. RD has been reviewed recently by Augustine [25], and Mao and Ye [26].…”