hydrogen deuterium helium nitrogen oxygen ozone fluorine neon argon krypton xenon cæsium mercury methane deuterated methane methanol ethane ethanol ethylene acetylene propane 2-propanol cyclo propane propylene isobutane n-butane neopentane n-pentane silane germane DME ammonia nitric oxide nitrous oxide carbon monoxide carbon dioxide water vapour dimethoxymethane trifluoromethane trifluorobromomethane tetrafluoromethane tetra/pentafluoroethane hexafluoroethane octafluoropropane sulphur hexafluoride boron trifluoride hydrogen sulphide carbon disulphide carbonyl sulphide