NMR Line shape and cross relaxation of tunneling ammonium protons in (NH4)2ZnCl4

Autor:	E.E. Ylinen, Marko Patrick John Punkkinen, A.H. Vuorimäki
Rok vydání:	1989
Předmět:	Dipole Chemistry Stereochemistry Proton NMR Time constant General Physics and Astronomy Second moment of area Magnetization transfer Physical and Theoretical Chemistry Molecular physics Quantum tunnelling Line (formation) Ion
Zdroj:	Chemical Physics Letters. 161:561-566
ISSN:	0009-2614
DOI:	10.1016/0009-2614(89)87038-1
Popis:	The second moment M2 of the proton NMR spectrum and the time constant TSD of the magnetization transfer between the protons of the A and T symmetry species of NH4+ ions were measured as functions of crystal orientation and temperature down to 4.5 K in (NH4)2ZnCl4. M2 increases in two steps with decreasing temperature and shows, between the steps, a strong dependence on orientation. TSD has a maximum of 3 ms at 12 K. The TSD data and earlier results on T1D, the spin-lattice relaxation time of the dipolar energy, are compared with a model. The results are explained by the presence of two kinds of ammonium sites in this compound.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::16d9ed8bb577e714279d40171d2c0e56 https://doi.org/10.1016/0009-2614(89)87038-1 Zobrazit plný text záznamu