PIRSS and LEED investigations of HN3 adsorbed on NaCl(100)

Heidberg, J.; Hustedt, Michael; Oppermann, J.; Paszkiewicz, P.

doi:10.1016/0039-6028(95)01178-1

Cited by 6 publications

(14 citation statements)

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“…10 The absence of ammonium azide formation during any annealing experiments on Au (Figure 2) argues strongly that H 2 O is necessary for NH radical formation and hence ammonium azide production. Once formed, NH 4 + N 3remains stable until ≈230 K consistent with the desorption characteristics of the same species observed by Heidberg et al 9 Ammonium azide formation could in principle also arise from reactions initiated between N 3and the ice film during sublimation. However, the close correlation between HN 3 desorption from the R-state and the increase in V a (N 3 -) band intensity (Figure 5, inset) suggests that reactions associated with HN 3 are at least in part responsible for ammonium azide formation.…”

Section: Discussionsupporting

confidence: 86%

“…Mechanism of Ammonium Azide (NH 4 + N 3 -) Formation. Adsorbed HN 3 has previously been reported to transform into ammonium azide 9,33 under the influence of UV irradiation. Based on these observations, the initial step in NH 4 + N 3formation during X-ray irradiation is hypothesized to involve the production of NH radicals by electron impact dissociation of HN 3 , which have previously been identified as products in the electron beam dissociation of gas-phase HN 3 : 4,34,35 Subsequent abstraction reactions between NH radicals and adsorbed HN 3 molecules lead to NH 3 production, whose reaction with HN 3 yields NH 4 + N 3 -.…”

Section: Discussionmentioning

confidence: 99%

“…For example, using polarization-FT-infrared surface spectroscopy Heidberg et al have shown that hydrazoic acid adsorbs molecularly on NaCl, decomposing under the influence of UV irradiation to form ammonium azide (NH 4 + N 3 -). 9 Thoms and Russel have reported that hydrogen azide adsorbs molecularly on hydrogenated diamond surfaces but decomposes on the bare C(100) surface to form carbon azide. 10 The driving force for this reaction was postulated to be the relative strength of the C-H bond vs the Si-H or Ge-H bonds which favors N-H rather than N-N bond cleavage.…”

Section: Introductionmentioning

confidence: 99%

“…The chemistry of HN 3 has also been studied on less reactive surfaces with a view toward surface modification. For example, using polarization-FT-infrared surface spectroscopy Heidberg et al have shown that hydrazoic acid adsorbs molecularly on NaCl, decomposing under the influence of UV irradiation to form ammonium azide (NH 4 + N 3 - ) . Thoms and Russel have reported that hydrogen azide adsorbs molecularly on hydrogenated diamond surfaces but decomposes on the bare C(100) surface to form carbon azide .…”

Section: Introductionmentioning

confidence: 99%

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Thermal and Electron-Induced Reactions of Hydrazoic Acid (HN₃) Adsorbed on Gold and Ice

2001

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The chemistry of hydrazoic acid (HN 3 ) on polycrystalline gold and amorphous ice was studied as a function of HN 3 exposure, temperature, and X-ray irradiation using reflection absorption infrared spectroscopy (RAIRS) and X-ray photoelectron spectroscopy (XPS). On Au, HN 3 was found to adsorb molecularly at 100 K. In contrast, at 100 K the reaction of HN 3 with ice was dominated initially by deprotonation and the formation of azide ions (N 3 -). At higher HN 3 exposures on ice, RAIRS data was consistent with molecular adsorption, although a distinct, more strongly bound molecular state was also observed that is attributed to hydrogen bonding between H 2 O and HN 3 . Annealing HN 3 adsorbed on Au resulted in predominantly molecular HN 3 desorption while in the HN 3 /ice system molecular desorption was accompanied by the production of ammonium azide (NH 4 + N 3 -). In contrast, NH 4 + N 3was not observed on the Au surface during annealing experiments. The formation of NH 4 + N 3is postulated to derive from the reactions of NH radicals, formed as a result of NN-NH bond cleavage, within the adsorbate layer. In both the HN 3 /ice and HN 3 /Au systems, secondary electrons generated by X-ray irradiation induced NH 4 + N 3formation and nitrogen desorption, which are consistent with the following net reaction: 4HN 3(a) f NH 4 + N 3(a)-+ 4N 2(g) v

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal and Electron-Induced Reactions of Hydrazoic Acid (HN₃) Adsorbed on Gold and Ice

2001

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“…A first characterization of this system has been carried out by means of PIRS [67]. Molecular adsorption of HN 3 on NaCl(100) is observed.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Hydrogen Azide on the NaCl(100) Single Crystal Surface. Orientational and Translational Ordering of the HN3 Monolayer as Revealed by PIRS, LEED and Spectra Simulation

Heidberg¹,

Hustedt²,

Oppermann³

et al. 2001

Zeitschrift Für Physikalische Chemie

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The adsorption of hydrogen azide HN 3 on NaCl(100) has been studied by means of polarization Fourier transform infrared spectroscopy PIRS and low energy electron diffraction LEED. The well-defined surface was prepared in-situ under UHV by cleaving a single crystal with as few dislocations as possible.Ordered molecular adsorption of HN 3 has been observed. Multiple absorptions of all four molecular vibrations with frequencies between 4000 and 1000 cm −1 , all nondegenerate in the gas, are found at 120 K. In particular, a quartet of strongly polarized sharp absorption lines for the asymmetric stretching vibration ν 2 at 2162.8, 2154.0, 2149.2, and 2138.3 cm −1 is obtained, the line at 2162.8 cm −1 being extremely weak in s-polarization. Saturation of adsorption, indicating the monolayer, is observed both upon dosing HN 3 in the low coverage range, where island growth is inferred, and desorbing HN 3 from multilayers. No domain orientation appears to be preferred. An activation energy of desorption of 43 ± 5 kJ/mol and a pre-exponential factor of 2.6 × 10 14±1.5 s −1 were determined.Isotopic mixture experiments with H 14 N 3 and H 14 N 15 N 14 N reveal that the four absorption lines of the ν 2 vibration are caused first by site splitting due to two energetically inequivalent HN 3 -species and second by Davydov splitting due to a strong correlation field between the dynamic dipoles. There are four molecules per adsorbate unit cell: two different pairs of energetically equivalent but translationally inequivalent molecules. Further, two different pairs of NH hydrogen bonds are observed. Tilt angles and intermolecular angles of the adsorbed molecules were determined. The translational symmetry of the adsorbate was derived by LEED. Simulation of the ν 2 quartet spectrum based on equations of classical electrodynamics was accomplished yielding the angles, lateral distances and dynamic vibrational couplings within the monolayer. Combining all results we propose a monolayer structure of angularly ordered zigzag chains of HN 3 molecules, where two molecules are linked by a hydrogen bond forming a dimer, while the other weaker hydrogen bond ties the dimers together or to a Cl − surface ion. Two HN 3 dimers make up the p(2 × 2) monolayer unit cell of 2D space group pg.

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Adsorption and reactions of HN3 on Si(100)-2×1: A computational study

2006

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PIRSS and LEED investigations of HN3 adsorbed on NaCl(100)

Cited by 6 publications

References 13 publications

Thermal and Electron-Induced Reactions of Hydrazoic Acid (HN₃) Adsorbed on Gold and Ice

Thermal and Electron-Induced Reactions of Hydrazoic Acid (HN₃) Adsorbed on Gold and Ice

Adsorption of Hydrogen Azide on the NaCl(100) Single Crystal Surface. Orientational and Translational Ordering of the HN3 Monolayer as Revealed by PIRS, LEED and Spectra Simulation

Adsorption and reactions of HN3 on Si(100)-2×1: A computational study

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PIRSS and LEED investigations of HN3 adsorbed on NaCl(100)

Cited by 6 publications

References 13 publications

Thermal and Electron-Induced Reactions of Hydrazoic Acid (HN3) Adsorbed on Gold and Ice

Thermal and Electron-Induced Reactions of Hydrazoic Acid (HN3) Adsorbed on Gold and Ice

Adsorption of Hydrogen Azide on the NaCl(100) Single Crystal Surface. Orientational and Translational Ordering of the HN3 Monolayer as Revealed by PIRS, LEED and Spectra Simulation

Adsorption and reactions of HN3 on Si(100)-2×1: A computational study

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Thermal and Electron-Induced Reactions of Hydrazoic Acid (HN₃) Adsorbed on Gold and Ice

Thermal and Electron-Induced Reactions of Hydrazoic Acid (HN₃) Adsorbed on Gold and Ice