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The surface region of a material is significantly different from the bulk phase of the same material, which could be designated as the surface-state of the material. The important interfacial phenomena and characteristics such as adhesion, biocompatibility, and corrosion are governed by the interaction between the contacting surface-states. The interfacial interaction occurs towards establishing the equilibrium between the surface-states. The concept of the surface-states equilibration is applied to the fundamental step of creating electric glow discharge of gases using experimental data available in literature for argon and helium. The surface-state of material contains varying amount of free to loosely bound electrons depending on the electro negativity of constituent atoms of the material. When an interface is created by making contact between two dissimilar materials, e.g., metal/polymer, polymer A/polymer B, etc., the transfer of surface-state electrons occurs in order to establish equilibrium between the two surface-states. The electrical breakdown of gas phase in low-pressure DC discharge, which has been known as Paschen curve or Paschen law in classical physics of electrical discharge can be explained by this approach. While classical approach depends on the creation of the primary electrons in the gas phase by hypothetical mechanisms that causes ionization of gas atoms and the subsequent secondary electrons emission from the cathode surface by the bombardment of ions, our analysis indicates that the primary electrons originate from the cathode surface-state electrons. When the electric field reaches the critical value for the gas phase dielectric breakdown as the potential is increased, the electric field profile changes to that in the cathode fall region, which is the surface-state of the electrically broken-down gas phase contacting with the cathode, and the conductivity of gas phase changes in orders of magnitudes (106 - 107) and causes the electron avalanche. Thus the dielectric breakdown of gas phase precedes the ionization of gas, which explains why helium having the higher ionization energy than argon breaks down at lower voltage. The concept of the surface-states equilibration in the metal/gas under electric field is presented. |