Fig. 4: Long-term evolution of NMR spectra in days after initial laser heating at 170 GPa.
From: Diffusion-driven transient hydrogenation in metal superhydrides at extreme conditions
a 139La-NMR spectra remain almost constant intensities while resonance frequencies gradually shift towards higher Hz/MHz values. b A progressive decrease in signal-intensity of the 1H-NMR spectra of the metal hydride spin sub-system was observed while a simultaneous increase of molecular hydrogen in the sample cavity (c) was observed. Red lines are a guide to the eye. Carrier frequencies f0 are identical to Fig. 1. Lanthanum and hydrogen shifts were referenced to an aqueous solution of Lanthanum chloride and Tetramethylsilane (TMS). Supplementary Figs. S4–S9 show similar data for all other experimental runs.
