[PDF]     https://doi.org/10.3952/physics.2026.66.1.7

Open access article / Atviros prieigos straipsnis
Lith. J. Phys. 66, 61–68 (2026)
 

ON THE PROTON SPIN DIFFUSION IN POWDERED FUMARIC ACID
  Laurynas Dagys
Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio 3, 10257 Vilnius, Lithuania
Email: laurynas.dagys@ff.vu.lt

Received 1 December 2025; accepted 21 January 2026

Spin diffusion is a well-established phenomenon in solid-state NMR, providing means to probe the molecular structure and transfer magnetization over extended intramolecular distances. Recently, we demonstrated that highly polarized 13C nuclei in 1-13C-fumaric acid can relay magnetization across crystallite boundaries to other 13C-labelled powders. To explore the possibility of using the abundant 1H network, in the present study, dry powdered fumaric acid was examined using conventional solid-state NMR techniques characterizing local order, relaxation and dynamical properties. The results reveal that, although 1H spin diffusion is intrinsically slow, both the diffusion rate and polarization lifetime increase with temperature. This offers new practical insights into the proton-mediated spin diffusion and may aid in designing more efficient polarization-relay strategies.
Keywords: solid-state NMR, spin diffusion, cross-polarization


APIE PROTONŲ SUKINIO DIFUZIJĄ MILTELIŲ PAVIDALO FUMARO RŪGŠTYJE
Laurynas Dagys
Vilniaus universiteto Fizikos fakulteto Cheminės fizikos institutas, Vilnius, Lietuva
 Sukinio difuzija yra plačiai paplitęs reiškinys kietojo kūno branduolinio magnetinio rezonanso (BMR) srityje, leidžiantis tirti molekulinę struktūrą ir pernešti magnetizaciją dideliais tarpmolekuliniais atstumais. Neseniai parodėme, kad stipriai poliarizuotų 13C branduolių poliarizacija gali būti perduodama netgi tarp atskirų kristalitų, pradedant nuo hiperpoliarizuotos 1-13C-fumaro rūgšties. Šiame darbe sausa miltelių pavidalo fumaro rūgštis buvo tiriama taikant įprastinius kietojo kūno BMR metodus, siekiant charakterizuoti sukinių difuzijos savybes tankiame 1H branduolių tinkle. Rezultatai rodo, kad nors sukinio difuzija šioje rūgštyje yra lėta, jos greitis ir poliarizacijos gyvavimo trukmė didėja kylant temperatūrai. Šie duomenys suteikia naujų įžvalgų apie protonų nulemtą sukinių difuzijos mechanizmą ir gali būti svarbūs kuriant efektyvesnes poliarizacijos perdavimo strategijas.


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