Electron-impact ionization of NO, NO2, and N2O

López, José L.; Tarnovsky, V.; Gutkin, Michael; Becker, K.

doi:10.1016/s1387-3806(02)01042-4

Cited by 37 publications

(63 citation statements)

References 21 publications

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“…There was no clear effect of T v on the ratio. The average NO þ x ratio of 3.5 is similar to the value of 3.0 measured for NO 2 (38), suggesting that a large fraction of RONO 2 decomposes on the vaporizer to RO þ NO 2 and that then NO 2 is ionized (33). By contrast, ratios for HNO 3 (0.5) (39) and NH 4 NO 3 (1.5 AE 0.1 for the instrument used in this experiment) are much smaller.…”

Section: Methodssupporting

confidence: 78%

Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry

Farmer

Matsunaga

Docherty

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

530

562

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Organonitrates (ON) are important products of gas-phase oxidation of volatile organic compounds in the troposphere; some models predict, and laboratory studies show, the formation of large, multifunctional ON with vapor pressures low enough to partition to the particle phase. Organosulfates (OS) have also been recently detected in secondary organic aerosol. Despite their potential importance, ON and OS remain a nearly unexplored aspect of atmospheric chemistry because few studies have quantified particulate ON or OS in ambient air. We report the response of a high-resolution time-of-flight aerosol mass spectrometer (AMS) to aerosol ON and OS standards and mixtures. We quantify the potentially substantial underestimation of organic aerosol O/C, commonly used as a metric for aging, and N/C. Most of the ONnitrogen appears as NO þ x ions in the AMS, which are typically dominated by inorganic nitrate. Minor organonitrogen ions are observed although their identity and intensity vary between standards. We evaluate the potential for using NO þ x fragment ratios, organonitrogen ions, HNO þ 3 ions, the ammonium balance of the nominally inorganic ions, and comparison to ion-chromatography instruments to constrain the concentrations of ON for ambient datasets, and apply these techniques to a field study in Riverside, CA. OS manifests as separate organic and sulfate components in the AMS with minimal organosulfur fragments and little difference in fragmentation from inorganic sulfate. The low thermal stability of ON and OS likely causes similar detection difficulties for other aerosol mass spectrometers using vaporization and/or ionization techniques with similar or larger energy, which has likely led to an underappreciation of these species.atmospheric chemistry | organic aerosol | organic nitrate | organic sulfate | SOA O rganonitrates (ON, i.e., RONO 2 ) and organosulfates (OS, i.e., ROSO 3 H) are known to be present in secondary organic aerosol (SOA) (1-4), and are a nearly unexplored but potentially important aspect of atmospheric chemistry. The mechanisms behind ON and OS production and aging are poorly understood and generally ignored in models due in part to a lack of measurement approaches. ON have recently been identified as significant components (15-35%) of NO y in the gas-phase (5, 6) and serve as indicators of ozone production (7). Oceans and certain industrial processes directly emit ON, but these are generally short-chain alkyl nitrates that exist only in the gas-phase and constitute a minor fraction of atmospheric ON (6,8). Most atmospheric ON are produced either by photochemical (OH-initiated) or nocturnal (NO 3 -initiated) oxidation reactions of anthropogenic and biogenic volatile organic compounds (VOCs). These reactions can produce large, multifunctional ON with vapor pressures potentially low enough to condense and form SOA. During photochemical oxidation of VOCs in the presence of nitrogen oxides, ON are minor products of peroxy radical ðRO 2 Þ þ NO reactions. These reactions produce ON with yields of ...

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Section: Methodssupporting

confidence: 78%

Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry

Farmer

Matsunaga

Docherty

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

530

562

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“…Recent data recorded on our apparatus for the ionization of N 2 O [22] is in excellent agreement with the latest reported PICSs [23] for formation of all the fragment ions that are formed. This latest work again indicates that considerable losses of energetic fragment ions occurred in earlier studies of PICSs [24,25].…”

Section: Experimental Apparatussupporting

confidence: 57%

The formation of boron containing fragment ions from the ionization of BCl3

Love

Price

2004

International Journal of Mass Spectrometry

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“…Additionally, despite all the above facts, the studies on the total ionization cross sections as well as the PICSs of N 2 O are scarce even at low energies of electron impact ( 1 keV) [2], [14][15][16][17][18][19]; some of the reported results [14,15] have significant deficiencies with regard to collecting the energetic ions. Large discrepancies are observed in the reported data for partial cross sections of fragment ions observed in the dissociative ionization of N 2 O at low energies of electron impact [14][15][16][17].…”

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confidence: 99%

Relative partial ionization cross sections of N2O under 10–25-keV electron impact

et al. 2012

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The relative partial ionization cross sections for the fragment ions produced in direct and dissociative ionization of a N 2 O molecule are measured for impact of 10-25-keV electrons by using an electron-ion-coincidence technique with a linear time-of-flight spectrometer. The six ionic fragments of N 2 O (N 2 O + , NO + , N 2 + , O + , N + , and N 2+ + O 2+ ) are observed and identified. The impact energy dependence of the partial ionization cross sections for these ions is expressed relative to the cross section of N 2 O + and is found to be nearly invariant. The relative ionic fractions for the produced ions of N 2 O are also obtained and compared with the earlier reported data available at lower energies of electron impact. It is found that the relative ionic fractions for singly charged fragments are almost energy independent. However, for the doubly charged fragment ions (N 2+ + O 2+ ), the present data are found to be higher by almost a factor of four compared to the relative ionic fraction reported earlier at a very low impact energy.

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Electron-impact ionization of NO, NO2, and N2O

Cited by 37 publications

References 21 publications

Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry

Response of an aerosol mass spectrometer to organonitrates and organosulfates and implications for atmospheric chemistry

The formation of boron containing fragment ions from the ionization of BCl3

Relative partial ionization cross sections of N2O under 10–25-keV electron impact

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