NMR instabilities and spectral clustering in laser-polarized liquid xenon - art. no. 184427

To study how highly magnetized liquids behave in NMR experiments, we have p erformed low-field NMR on laser-polarized liquid Xe-129, with nuclear polar ization of up to 6%. Contrary to conventional NMR results, we find that ins tabilities develop after a large pulse, leading to an unexpectedly abrupt d ecay of the signal. In contrast, the NMR spectrum after a small pulse colla pses to a series of unusually sharp lines (spectral clustering), whose widt hs correspond to precession lifetimes longer than a half minute. We discuss the key role of long-range dipolar coupling in such spin dynamics.