ISSN:
1434-6079
Keywords:
PACS. 33.15.Vb Correlation times in molecular dynamics - 33.15.Hp Barrier heights (internal rotation, inversion, rotational isomerism, conformational dynamics) - 33.25.+k Nuclear resonance and relaxation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract: 19 F and 11 B spin-lattice relaxation times were measured in [ Zn ( ptz ) 6 ] ( BF 4 ) 2 and in the spin-crossover compound [ Fe ( ptz ) 6 ] ( BF 4 ) 2 . For both compounds BF 4 - anion reorientation is active above 50 K. For [ Zn ( ptz ) 6 ] ( BF 4 ) 2 , the anion-reorientation dynamics is different in the temperature regions of 50-90 K, 90-120 K, and above 150 K; between 120 and 150 K it changes rapidly reflecting a structural change. In [ Fe ( ptz ) 6 ] ( BF 4 ) 2 the mechanism for the paramagnetic relaxation involving the 19 F nuclei is found to be of the diffusion-limited type according to the theory of Lowe and Tse. The present results prove that the spin-crossover takes place in a dynamic surrounding and not in a static crystal lattice.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s100530050382
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