Hyperfine splitting films

Table III. Hyperfine splitting (A) values of TEMPAMINE+ adsorbed on fully wetted oriented clay films.

Figure 6. Plot of TEMPAMINE hyperfine splitting as a function of orientation of the clay film (angle between plane of film and the applied magnetic field) for hectorite (O), montmorilIonite ( ) and beidellite (n).

Several general observations can be made from the spectra and the calculated ESR parameters. First, the Na+- smectites possess narrower resonance line widths than the Ca +-smectites, with the exception of the saponite. Since Ca +-smectites, unlike Na+ -smectites, do not disperse into individual platelets in aqueous suspension, the Na+-smectite films formed by drying suspensions onto a smooth flat surface have the silicate surfaces more perfectly oriented in the plane of the film. As a result, less angular variation of the z-axis of Cu + relative to the plane of the film would narrow the spectra. One can see evidence of hyperfine splitting in the gj component of the Na+-smectite spectra, but not in the Ca +-smectite spectra. Saponite, unlike the other smectites, has very similar spectral linewidths for the Na+ and Ca + form (Figure 16). Since this Na+-saponite sample does not disperse completely in water (Table II), the alignment of Na+-saponite platelets in the clay film may be no better than that of the Ca +-saponite. 

The absence of hyperfine splitting is due to intramolecular electron hopping between close ligand. In a similar fashion the EPR spectrum obtained at - 0.95 V (Ru couple) is typical of a film containing a Ru metal c tre. The g value is dien higher (g = 2.0132) confirming diat in this electrog erated species the electron is predominantiy metal centered. 

The films were polycrystalline by nature with well expressed angular dependence of the EPR spectra. Hyperfine splitting of spectra was not observed, which corresponds to a magnetically... 

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