Long-lived States in Multiple-Spin Systems

Long-lived spin states are excited in molecules featuring more than two isolated coupled spins, including amino acids. The figure shows the exponential recovery with the longest time-constant in aspartic acid, T1max=5.842±0.004 s, and of the decay of the long-lived state, TLLS=10.9±0.2 s). An improvement in spin memory by a factor 2 compared to longitudinal spin-lattice relaxation time constants is obtained for most systems.