Imidazole single crystal has a highly anisotropic conductivity; the ratio of conductivity in the c and a crystallographic directions is "'10 3 . In the c crystallographic direction, the hydrogen bonded direction, protonic carriers are discharged as hydrogen at the negative electrode. The limiting conduction process is possibly due to L-defect injection and transport back down the hydrogen bonded chain after the proton is discharged. Conductivity in the a direction is probably electronic and extrinsic.

There are three parameters in Eq. (2) which determine the behavior of the model and these can, within limits, be determined without reference to surface order. We took J 2 Mi as -0.2, quite close to the preferred value of -0.25 suggested in Ref. 7. To illustrate best the contrast between results from the bulk and from the surface, we adjusted J ± so that the calculated points for the bulk order parameter agree with experiment 4 up to the experimental transformation temperature. This gave J 1 /k = 23TK, a value about 7% higher than would have been obtained by the procedure of Ref. 7. Finally we let AE = 2.5^, corresponding to a constant average surface composition.In Fig. 4 we show the average of the order parameters for the two topmost Cu-Au layers, for the two boundary conditions of the surface model, together with the measured surface order and the calculated bulk order as a function of temperature. It appears from the figure that the difference between the observed behavior of the longrange order parameter at the surface and that in the bulk can be explained by a simple model involving only nearest-and next-nearest-neighbor interactions which are the same for both surface and bulk. Furthermore, it is evident from the analysis that consideration of a region of accommodation between surface and bulk is a necessary Considerable interest exists in examining the properties of both organic and inorganic structures which are highly anisotropic and can be visualized as containing one-dimensional chainsmetallic "spines"-surrounded by a matrix whose properties are highly important in determining the transport properties of that system. The or-feature of any model meant to describe the phenomenon of long-range order at a crystal surface.The temperature dependence of the electrical conductivity and Seebeck coefficient for the polymer chain system (SN) X has been measured along the chain axis from 4.2 to 300°K. The data show the system to be metallic over the entire temperature range studied, with a small conductivity maximum at ~33°K.

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Sulfur doped graphite is obtained by arc vaporization of graphite rods in the presence of thiophenes. The surfaces of the carbon rods become coated with a layer of a sulfur-doped carbon. X-ray diffraction indicates a small d spacing expansion, and there is a slight decrease in the electrical conductivity of the doped layer. X-ray photoelectron spectroscopy confirms that sulfur incorporation has occurred at a level of 0.6% and that the sulfur atoms are in a neutral state. X-ray photoemission results indicate that S incorporation induces a shift of the valence band toward the Fermi level.

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