question: When gas becomes plasma, what is happening to the molecules?
comment: The electrons become so energetic that they strip themselves away from the nuclei, essentially breaking first molecules and then atoms apart and becoming a soup of atomic nuclei and loose electrons.
passages: BULLET::::- Presence of "new gas phase species". In a plasma discharge a wide range of new species is produced allowing the catalyst to be exposed to them. Ions, vibrationally and rotationally excited species do not affect the catalyst since they loose the charge and the additional energy they possess when they reach a solid surface. Radicals, instead, show high sticking coefficients for chemisorption, increasing the catalytic activity.
  
  BULLET::::- Catalyst effects on plasma:
   Plasma is composed of gaseous matter that has been completely ionized, usually through high temperature.
  
  Section::::Modern principles.:Acidity and basicity.
   A dusty plasma contains tiny charged particles of dust (typically found in space). The dust particles acquire high charges and interact with each other. A plasma that contains larger particles is called grain plasma. Under laboratory conditions, dusty plasmas are also called "complex plasmas".
  
  Section::::Complex plasma phenomena.:Impermeable plasma.
   Even if the macroscopic electric field is zero, any single ion will experience an electric field due to the neighboring charged particles in the plasma. This results in a broadening of some lines that can be used to determine the density of the plasma.
  
  Section::::Passive spectroscopy.:Spectral line ratios.
  
  The brightness of an atomic spectral line emitted by atoms and ions in a gas (or plasma) can depend on the gas's temperature and pressure.
   Plasma is any gas whose atoms or molecules have been ionized, and is a separate phase of matter. This is most commonly achieved by heating the gas to extremely high temperatures, although other methods exist. Plasma becomes increasingly viscous at higher temperatures, to the point where other matter has trouble passing through.
   In accordance to the main sources, the emitted gases usually contain hydrogen (source type IIa), argon (for coatings obtained using PVD in Ar plasma - source type IIb), methane (source type III), water (source type I and/or III), carbon mono- and dioxide (source type I/III). 
  
  The knowledge on the mechanisms of MSGE is still vague. On the basis of the experimental findings it was speculated that the following processes can be related with MSGE:
  
  BULLET::::1. Transport of gas atoms by moving dislocations
  
  BULLET::::2. Gas diffusion in the bulk driven by gradient of mechanical stress
   BULLET::::- the main chamber, which is kept in UHV at a base pressure of ~10formula_1 mbar
  
  BULLET::::- the plasma source, where the plasma is generated.
   Dusty plasmas are often studied in laboratory setups. The dust particles can be grown inside the plasma, or microparticles can be inserted. Usually, a low temperature plasma with a low degree of ionization is used. The microparticles then become the dominant component regarding the energy and momentum transport, and they can essentially be regarded as single-species system. This system can exist in all three classical phases, solid, liquid and gaseous, and can be used to study effects such as crystallization, wave and shock propagation, defect propagation, etc.
   Plasma and ionized gases have properties and display behaviours unlike those of the other states, and the transition between them is mostly a matter of nomenclature and subject to interpretation. Based on the surrounding environmental temperature and density, partially ionized or fully ionized forms of plasma may be produced. Neon signs and lightning are examples of partially ionized plasma. The Earth's ionosphere is a plasma and the magnetosphere contains plasma in the Earth's surrounding space environment. The interior of the Sun is an example of fully ionized plasma, along with the solar corona and stars.
   Section::::Mathematical descriptions.
  
  To completely describe the state of a plasma, all of the
  
  particle locations and velocities that describe the electromagnetic field in the plasma region would need to be written down.
  
  However, it is generally not practical or necessary to keep track of all the particles in a plasma.
  
  Therefore, plasma physicists commonly use less detailed descriptions, of which
  
  there are two main types:
  
  Section::::Mathematical descriptions.:Fluid model.
   Section::::Mathematical descriptions.:Kinetic model.
   Plasmas in stars can both generate and interact with magnetic fields, resulting in a variety of dynamic astrophysical phenomena. These phenomena are sometimes observed in spectra due to the Zeeman effect. Other forms of astrophysical plasmas can be influenced by preexisting weak magnetic fields, whose interactions may only be determined directly by polarimetry or other indirect methods. In particular, the intergalactic medium, the interstellar medium, the interplanetary medium and solar winds consist of diffuse plasmas.
   BULLET::::- Ultra-fine cleaning. Reactive chemical species efficiently oxidize organic surface contaminants, converting them into carbon dioxide and water, which evaporate from the surface, leaving it in ultra-fine clean state.
  
  BULLET::::- Removal of weak boundary layers. Plasma removes surface layers with the lowest molecular weight, at the same time it oxidises the uppermost atomic layer of the polymer.
  
  BULLET::::- Cross-linking of surface molecules. Oxygen radicals (and UV radiation, if present) help break up bonds and promote the three-dimensional cross bonding of molecules.
   A gas is usually converted to a plasma in one of two ways, e.g., either from a huge voltage difference between two points, or by exposing it to extremely high temperatures. Heating matter to high temperatures causes electrons to leave the atoms, resulting in the presence of free electrons. This creates a so-called partially ionised plasma. At very high temperatures, such as those present in stars, it is assumed that essentially all electrons are "free", and that a very high-energy plasma is essentially bare nuclei swimming in a sea of electrons. This forms the so-called fully ionised plasma.
   BULLET::::- "Nonthermal plasmas" on the other hand are non-equilibrium ionized gases, with two temperatures: ions and neutrals stay at a low temperature (sometimes room temperature), whereas electrons are much hotter. (formula_14). A kind of common nonthermal plasma is the mercury-vapor gas within a fluorescent lamp, where the "electrons gas" reaches a temperature of 10,000 kelvins while the rest of the gas stays barely above room temperature, so the bulb can even be touched with hands while operating.
   BULLET::::- Reduction of metal oxides. Plasma discharges, ignited in the forming gas, typically containing 5 % of hydrogen and 95 % of nitrogen, produce large quantities of reactive hydrogen species. By contact with oxidized metal surfaces, they react with metal oxides reducing them to metal atoms and water. This process is particularly efficient in electric arcs burning directly on the substrate surface. It leaves the surface clean from the oxides and the contaminants.
   BULLET::::- "Reduced coke formation". When dealing with hydrocarbons, coke formation leads to a progressive deactivation of the catalyst. The reduced coke formation in presence of plasma reduces the poisoning/deactivation rate and thus extending the life of a catalyst.
   Plasma (physics)
  
  Plasma () is one of the four fundamental states of matter, and was first described by chemist Irving Langmuir in the 1920s. It consists of a gas of ions, atoms which have some of their orbital electrons removed, and free electrons. Plasma can be artificially generated by heating or subjecting a neutral gas to a strong electromagnetic field to the point where an ionized gaseous substance becomes increasingly electrically conductive, and long-range electromagnetic fields dominate the behaviour of the matter.
   Section::::Physical and chemical activation mechanisms.:Processes within the plasma volume.
   Section::::Introduction.
   BULLET::::- Local "electric field enhancement". This aspect is mainly related to a packed-bed PEC configuration. The presence of a packing material inside an electric field generates local field enhancements due to the presence of asperities, solid material surface inhomogeneities, presence of pores and other physical aspects. This phenomenon is related to surface charge accumulation on the packing material surface and it is present even if a packed-bed is used without a catalyst. Despite this is a physical aspect, it also affects the chemistry since it alters the electron energy distribution in proximity of the asperities.
   When matter becomes sufficiently hot, it becomes ionized and forms a plasma. This process breaks matter into its constituent particles which includes negatively-charged electrons and positively-charged ions. These electrically-charged particles are susceptible to influences by local electromagnetic fields. This includes strong fields generated by stars, and weak fields which exist in star forming regions, in interstellar space, and in intergalactic space. Similarly, electric fields are observed in some stellar astrophysical phenomena, but they are inconsequential in very low-density gaseous mediums.
   BULLET::::- "Discharges formation inside pores". This aspect is strictly related to the previous one. Small void spaces inside a packing material affect the electric field strength. The enhancement can also lead to a change in the discharge characteristics, which can be different from the discharge condition of the bulk region (i.e. far from the solid material). The high intensity of the electric field can also lead to the production of different species that are not observed in the bulk.
   Section::::Properties and parameters.:Temperature.:Fully vs. partially (weakly) ionized gases.
   Studying astrophysical plasmas is part of mainstream academic astrophysics. Though plasma processes are part of the standard cosmological model, current theories indicate that they might have only a minor role to play in forming the very largest structures, such as voids, galaxy clusters and superclusters.
  
  Section::::Early history.
  
  Norwegian explorer and physicist Kristian Birkeland predicted that space is filled with plasma. He wrote in 1913: Birkeland assumed that most of the mass in the universe should be found in "empty" space.
  