Determination Of Work Function Research Articles

分子軌道法, ポーラログラフおよび吸収スペクトルによる感光性色素の仕事関数の決定

分子軌道法, ポーラログラフおよび吸収スペクトルによる感光性色素の仕事関数の決定

The determination of work function from the ratio of positive to negative surface ionization of an alkali halide

The work function and its temperature dependency has been measured for a (110) oriented tungsten surface in the temperature range 1800 to 2200 °K. The method consisted of determining the ratio of positive to negative surface ionization of a NaCl beam impinging on the (110) tungsten surface. The recent spectroscopic determination of the halogen electron affinities makes possible a reliable calculation of the work function from these data. The results are compared with those obtained independently by the more conventional retarding potential method. Mean values for the parameters in the equation φ = φ 0 + αT for the (110) tungsten surface are φ 0 = 5.03 ± 0.15eV and α = −(1.4 ± 0.2) × 10 −4 eV °K .

Ionization on Tungsten Single-Crystal Surfaces

Surface ionization of atomic beams of strontium or calcium from the [110] and the [111] directions of tungsten was studied mass-spectrometrically. Results consistent with the Saha—Langmuir relation indicate that the method is applicable for the determination of first ionization potentials or work functions. A value for the work function of the [110] direction is 5.41±0.04 eV. A value for the [111] direction of tungsten is 4.49±0.04 eV.

Work function measurements in experimental tubes containing cathodes of uranium and zirconium carbides

Work function measurements are reported for carburized tantalum cathodes coated electrophoretically with uranium and zirconium carbides. Thermionic methods for the determination of work function have been used together with the Zisman modification of the Kelvin technique. The poor agreement found between the two sets of results is thought to indicate that thermionic emission takes place from only a fraction of the total cathode area. Work function measurements have also been made on the thin films that evaporate from these cathodes during their operation at high temperatures on to fized anodes. When the cathode is uranium carbide, our measurements can be interpreted in terms of an evaporated film of uranium metal and uranium monoxide on the anode surface. All of this work has been performed under ultra-high vacuum conditions. The mean work function values for tubes containing uranium carbide cathodes are as follows: the work function from the Kelvin measurements at 300°K is 3·81 ± 0·01 eV and that from the slope of a Richardson line plotted from retarding field data and applying to 0°K is 2·9 ± 0·1 eV. The temperature coefficient of the work function of uranium carbide is 5 × 10 −4 eV per deg. For zirconium carbide cathodes the mean values are: 3·62 ± 0·01, 2·5 ± 0·1 and 7 × 10 −4 eV per deg. The work function of the anode in a tube containing a uranium carbide cathode reaches a constant value in a few hours of 3·0 ± 0·1 eV. This, like the Kelvin results quoted above, is an arithmetic average over the area of any high and low work function patches and in this case applied to the unmeasured temperature of the anode when the cathode was operating at 1300°K.

Determination of electron work function in solids by a vibrating condenser method

Functional sub-micrometer core/shell hybrid particles coated with inorganic components have many promising applications as new materials based on their multiphase structures with unusual features. Herein we demonstrate a novel approach to produce such particles with potential applications in the fields of magnetic materials. PSt seed latex was prepared through emulsion polymerization. Core–shell P(St-co-Am) particles with polyacryamide (PAm)-rich shell were formed through interfacial-initiated seeded emulsion polymerization. Then spherical P(St-co-AM)/NiS sub-micrometer composites were successfully prepared by the reaction of nickelous sulfate (NiSO4) and thioacetamide (CH3CSNH2) under 60Co γ-irradiation at ambient temperature and pressure. P(St-co-AM)/NiS hybrid particles were confirmed with electron microscopy, X-ray diffraction and X-ray photo-electron spectroscopy. The properties of P(St-co-Am) hybrid particles were studied with UV–vis spectroscopy, photoluminescence spectroscopy and magnetic hysteresis loop analysis.