87Rb Spin Diffusion in Ferroelectric RbH2PO4Studied by Two Dimensional Exchange NMR

Alkali Tin Halides: Exploring the Local Structure of A2SnX6 (A = K, Rb; X = Cl, Br, I) Compounds Using Solid-State NMR and DFT Computations

“…Similar to 39 K, 87 Rb ( I = 3/2, 27.8% N.A.) is a quadrupolar nucleus that can be difficult to study due to the frequent presence of large quadrupole coupling constants. , However, 87 Rb is more sensitive than 39 K due to its more favorable gyromagnetic ratio (∼1/3rd that of 1 H), which has enabled the successful study of this nucleus in many materials at moderate magnetic field strengths in the past. ,,− The 87 Rb NMR spectra under both MAS and nonspinning conditions are shown in Figure and fitted NMR parameters are shown in Table . The isotropic chemical shift decreases from Rb 2 SnCl 6 (13 ppm) to Rb 2 SnBr 6 (−6 ppm), and under MAS ( v r = 8 kHz, Figure a), peaks for the cubic Cl and Br compounds are sharp with fwhm of 105 ± 5 and 341 ± 10 Hz, respectively.…”

Phonon-Assisted Spin Diffusion in Solids

“…[37] for the 87 Rb spin diffusion in ferroelectric RbH 2 PO 4 , where the presence of spin diffusion between the 87 Rb nuclei was demonstrated unambiguously (16). The 87 Rb second moment was determined there to be M 2 ϭ 6 ϫ 10 8 s Ϫ2 , and the Debye temperature in this crystal is known to be about 400 K, yielding D Ϸ 5 ϫ 10 13 s Ϫ1 .…”