Skalare Kern-Elektronen-Wechselwirkungen zwischen verschiedenen Molekülen in Lösungen
Open Access
- 1 February 1966
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung A
- Vol. 21 (1-2) , 153-157
- https://doi.org/10.1515/zna-1966-1-223
Abstract
The dynamic polarization of the 19F nuclei in free radical solutions of C6F6, C6H5F and C6H4F2 is much less negative than expected from investigations of the proton polarization in similar systems. In the limits of “extreme narrowing” the enhancement factor is of the order of —100 instead of —350; in strong magnetic fields it is even posiitve. Data obtained in fields of 16.2, 176 and 3230 gauss are interpreted in terms of a combined dipole-dipole and scalar coupling between nuclear and electron spins. For the time dependence of the dipolar interaction the model of an independent "translational" random diffusion of spin-carrying molecules is used whilst the scalar interaction is described by a spectral function proportional to τSk/(1+ω2τSk 2). The results are compared with measurements of RICHARDS in strong magnetic fields and with theoretical models of HUBBARD for the scalar interaction. Diffusional and scalar correlation times, the relative contribution of the scalar interaction and the order of the coupling constant are calculated.Keywords
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