Residual Gas Effect on Photofield Emission from Tungsten (111) Face

Using the photofield emission method, surface states and bulk excitations from clean and residual gas adsorbed (111) face of tungsten were measured. Residual gas shaded the surface states and diminished photoemission from the bulk excitations. Gas of the artificially increased background pressure 10$\text{}^{-8}$ Pa adsorbed during the measurement deforms the photocurrent-voltage characteristic; the optical excitations observed for clean surfaces are exhibited, diminished or lost. For the adsorbed (111) face the state related to the metal-gas surface has been observed.