Exact evaluation of the line-narrowing effect of the Lee–Goldburg pulse sequence in solid-state NMR spectroscopy

Magic-angle irradiation or the Lee–Goldburg (LG) pulse sequence are routinely being used in high resolution NMR spectra of solids to suppresses the homonuclear dipolar interaction while simultaneously scaling the chemical shift and heteronuclear dipolar interactions. In this Letter, a general and detailed spin dynamics calculation procedure to evaluate the performance of the LG sequence is presented which yields an expression for the dipolar scaling factor for an arbitrary rf strength, rf offset and windowed observation. This analysis is expected to be useful in designing new multiple-pulse sequences for scaling the dipolar interaction.