title: Uptake of NH(3) and NH(3) + HOBr reaction on ice surfaces at 190 K.
abstract: The uptake of NH3 and the heterogeneous reaction of NH3 + HOBr --> products on ice surfaces at 190 K have been investigated in a flow reactor coupled with a differentially pumped quadrupole mass spectrometer. The uptake coefficient gammat for NH3 was determined to be (3.8 +/- 1.4) x 10(-4) on ice films at 189.8 K, for a partial pressure of NH3 in the range of 7.0 x 10(-7) to 3.8 x 10(-6) torr. The amount of NH3 uptake on the ice film was determined to be >2.9 x 10(15) molecules/cm(2), based on the total ice surface area at 189.2 K. The heterogeneous reaction of NH3 + HOBr on ice surfaces has been studied at 190 K. The reaction probability gammat was determined to be (5.3 +/- 2.2) x 10(-4) and was found to vary insignificantly as HOBr surface coverage changes from 2.1 x 10(13) to 2.1 x 10(14) molecules/cm(2). A reaction pathway is proposed on the basis of experimental observations.
authors.affiliation: Department of Chemistry, Shanghai Normal University, Shanghai 200234, China.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Jin
authors.forename: Liang T
authors.initials: LT
authors.lastname: Chu
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D001959:Bromates / Q000737:chemistry*; D003080:Cold Temperature; D007053:Ice; D013058:Mass Spectrometry; D010313:Partial Pressure
chemical_list: D001959:Bromates; D007053:Ice; D000641:Ammonia; C027664:hypobromous acid