Torsional Spectroscopy by NMR in the Rotating Frame

Nuclear-spin Zeeman states prepared at a low temperature in the rotating frame were matched to the torsional ground-state splittings of N${\mathrm{H}}_4$ and C${\mathrm{H}}_3$ groups in solid lattices at a higher temperature. A resonant transfer of order was observed to occur instantaneously. Measurements yield a part of the torsional spectrum and the torsional relaxation time. From the torsional relaxation, the torsional lifetime broadening of a N${\mathrm{H}}_4$ ground state in ammonium iodide at 10 K was found to be ∼ 1 Hz.