Effect of greenhouse gases (CO₂ and NO₂) on the secondary electron yield of Cu (110) surfaces

We investigate how adsorption of greenhouse gases on (110) copper surfaces alters the secondary electron emission. Secondary electron yields of the surfaces, covered with the greenhouse gas CO₂ and the indirect greenhouse gas NO₂, have been studied by employing combined first principles methods for the material properties and Monte Carlo simulations. In both cases, the secondary electron yields with respect to the clean surface increase. The physical reasons behind the increase of the yield for each system from an electronic perspective are discussed. It is shown that higher electronic emission yield results from weak bonding of the CO₂ layer with the Cu host because the surface provides an additional source of secondary electrons. Moreover, the presence of the NO₂ adsorbate creates a surface electric field, which changes the surface electron energy and increases the electron escape probability.