title: Photoinduced formation of N2 molecules in ammonium compounds.
abstract: Via fluorescence yield (FY) and resonant inelastic scattering spectroscopy in the soft X-ray range we find that soft X-rays induce formation of N2 molecules in solid NH4Cl and in related compounds. The nitrogen molecules form weak bonds in NH4Cl, so that a substantial fraction of the molecules remains in the sample. From measurements of the FY as a function of exposure and temperature, the rates for the photochemical processes are estimated. At elevated temperatures (363 K), several nitrogen atoms are removed from the sample per incoming photon. At lower temperatures (233 K), the rate is reduced to around 0.02 nitrogen atoms for each incoming photon. Virtually all these atoms form N2 molecules which are bound in the sample. The generality and implications of these results are briefly discussed.
authors.affiliation: BESSY, Albert-Einstein Str. 15, D-12489 Berlin, Germany. emad@bessy.de
authors.forename: Emad F
authors.initials: EF
authors.lastname: Aziz
authors.forename: Johan
authors.initials: J
authors.lastname: Gråsjö
authors.forename: Johan
authors.initials: J
authors.lastname: Forsberg
authors.forename: Egil
authors.initials: E
authors.lastname: Andersson
authors.forename: Johan
authors.initials: J
authors.lastname: Söderström
authors.forename: Laurent
authors.initials: L
authors.lastname: Duda
authors.forename: Wenhua
authors.initials: W
authors.lastname: Zhang
authors.forename: Jinglong
authors.initials: J
authors.lastname: Yang
authors.forename: Stefan
authors.initials: S
authors.lastname: Eisebitt
authors.forename: Christel
authors.initials: C
authors.lastname: Bergström
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Joseph
authors.initials: J
authors.lastname: Nordgren
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eberhardt
authors.forename: Jan-Erik
authors.initials: JE
authors.lastname: Rubensson
mesh_terms: D002627:Chemistry, Physical / Q000379:methods; D003460:Crystallization; D006859:Hydrogen / Q000737:chemistry; D008027:Light; D015233:Models, Statistical; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry*; D010777:Photochemistry / Q000379:methods*; D017785:Photons; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence / Q000379:methods; D013052:Spectrometry, X-Ray Emission / Q000379:methods; D013696:Temperature; D014965:X-Rays
chemical_list: D000644:Quaternary Ammonium Compounds; D006859:Hydrogen; D009584:Nitrogen