The emission of thermal positive ion(K
+), negative ion(F
-)and of neutral molecules(mainly KF)from a KF-Pt system is investigated as a function of both surfacev temperature(T)and mean sample layer thickness(θ). Thermochemical analysis of the results obtained indicates that K
+, F
- and KF are emitted from respectively different surface sites(Q(K
+), Q(F
-)and Q(KF))of the system. The actual surface areas (S(K
+), S(F
-)and S(KF))for the emission of K
+, F
-;and KF from the respective sites are found to be quite different from the apparent surface area. S(KF)is strongly dependent upon θ in contrast to S(K
+). Both S(K
+)and S(F
-)are estimated to be smaller by a factor of at least10
2than. S(KF). The difference in average effective work function between the active sites Q(K
+)and Q(F
-)is evaluated to be about3eV at θ≅10
2molecular layers at T≅700-750°K.
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