The photodissociation of tert-butyl nitrite adsorbed on Ag(111): bimodal velocity distributions of the photoproducts

Jenniskens, Hans G.; Essenberg, Wouter van; Kadodwala, Malcolm; Kleyn, Aart W.

doi:10.1016/s0009-2614(97)00154-1

Cited by 16 publications

(16 citation statements)

References 18 publications

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“…Recently we have investigated the surface photochemistry of tert -butyl nitrite adsorbed on Ag(111) at 355 nm. , From our studies we inferred that dissociation proceeds via the same excitation mechanism as in the gas phase. In this article we will report on the photochemistry at other wavelengths (532 and 266 nm) in order to explore the excitation mechanism in more detail.…”

Section: Introductionmentioning

confidence: 84%

“…The coverage and wavelength dependence of surface photochemistry yield important information on the excitation mechanism. − The coverage dependence was used to study the dissociation mechanism of tert -butyl nitrite at 355 nm corresponding to a photon energy of 3.5 eV. , In this paper we address the wavelength dependence. If dissociation is governed by a direct excitation, i.e., direct photoabsorption by the molecule, a photon resonance may be observed as is shown for Mo(CO) 6 adsorbed on Ag(111) .…”

Section: Introductionmentioning

confidence: 99%

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The Wavelength Dependence of tert-Butyl Nitrite Surface Photochemistry

et al. 1998

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The surface photochemistry of tert-butyl nitrite adsorbed on Ag(111) was investigated at 532 and 266 nm. The desorbing molecules were detected in time of flight (TOF) mode by a mass spectrometer. Irradiation of the adsorbates leads to desorption of NO at both wavelengths. At these wavelengths caging and bimodal NO TOF distributions, consisting of a hyperthermal and a thermal component, are observed. At 532 nm dissociation is governed by a direct excitation with a cross section of 2 × 10-21 cm2. The observed TOF distributions at 266 nm are very similar to the 355 nm results, although generally higher translational energies and cross section values (2 × 10-19 cm2) were measured. At 266 nm dissociation proceeds via a direct excitation. The results are consistent with an excitation into the S 1 state at 355 nm and excitation into the S 2 state at 266 nm.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

The Wavelength Dependence of tert-Butyl Nitrite Surface Photochemistry

et al. 1998

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“…In a similar analysis, bimodal distributions have been used to describe the photolysis of molecular clusters of TBN and TBN adsorbed on MgF 2 . [15][16][17][18][19][20][21] For 193-nm surface photodissociation, trimodal translational distributions adequately fit the spectra, the collisionless component tracks the gas-phase dissociation mechanism, 11 and the intermediate and thermal components display behaviors similar to those found for photolysis at 248 and 351 nm. [23][24][25] Although the photon energy is higher (6.5 compared to 5.0 eV), the characteristic translation energy of collisionless NO (0.55 eV) is lower than for 248 nm (0.89 eV).…”

Section: -Nm Tbn Photodissociation Processmentioning

confidence: 93%

“…When adsorbed, adsorbateadsorbate and adsorbate-substrate interactions do not significantly alter the dissociation of alkyl nitrites but do alter the subsequent dynamics and thereby alter the internal and translational energy distributions. [15][16][17][18][19][20][21][22][23][24][25] To complement previous studies, [22][23][24][25] in this paper we extend the excitation wavelength to 193 nm. Both resonance-enhanced multiphoton ionization time-of-flight (REMPI-TOF) and quadrupole mass spectrometer time-of-flight (QMS-TOF) tools were employed to study the NO dynamics produced by TBN photodissociation.…”

Section: Introductionmentioning

confidence: 99%

Photodissociation at 193 nm of tert-Butyl Nitrite on Ag(111)

et al. 2004

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The translational and internal state properties of nitric oxide, NO, ejected by 193-nm photodissociation of tert-butyl nitrite, (CH 3 ) 3 CONO, TBN, adsorbed on Ag(111) have been investigated using resonance-enhanced multiphoton ionization time-of-flight (REMPI-TOF) and quadrupole mass spectrometer time-of-flight (QMS-TOF). The results are described in terms of three components depending on the number of collisions along the exit trajectory and are compared to prior work using 248-and 351-nm photons. Although 193-nm photons have higher energy, the characteristic translational energy of the collisionless NO (0.55 eV) lies between that for 248 nm (0.89 eV) and 351 nm (0.39 eV). As for gas-phase photolysis at 193 nm, the NO is rotationally cold (J max ) 15.5), much lower than for both 248-(J max ) 53.5) and 351-nm (J max ) 31.5) photolysis. The NO vibrational distribution is dominated by V′′ ) 1, whereas V′′ ) 0 for 248 nm and V′′ ) 1 and 2 for 351 nm photodissociations, respectively. Angle-resolved REMPI-TOF and QMS-TOF studies give information about the orientation of adsorbed TBN. While TBN is more stable with the C-O-NdO plane perpendicular to surface and the internal O-N bond directed about 40°away from the surface normal, dosing less than a full monolayer at 80 K does not achieve this state fully. Annealing to 110 K is sufficient to realize this molecular orientation. For multilayer coverage dosed at 80 K, the data are consistent with considerable surface roughness compared to a surface annealed at 110 K. IntroductionSurface photochemistry has been of interest for many years. 1-3 Among the motivations are its many potential technological applications, e.g., photochemical lithography, deposition, and etching related to the fabrication of electronic and chemical sensor devices with submicron dimensions. There also continues to be scientific interest in fundamental questions concerning the mechanisms of energy transfer among the radiation field, and the various electronic and nuclear degrees of freedom of adsorbate-substrate systems.The spectroscopy and photodissociation dynamics of aliphatic nitrites (R-O-NdO) have been the subject of much interest. [4][5][6][7][8][9] Typically, gas phase and adsorbed nitrites dissociate upon photolysis and do so through cleavage of the internal O-N bond to from an alkoxide and nitric oxide. Like other nitrites, tertbutyl nitrite (TBN, (CH 3 ) 3 CONO) has three distinct optical absorption bands, the lowest energy band is found between 300 and 400 nm (n f π*, S 1 r S 0 ), and motion on S 1 is characterized as vibrational predissociation. The second band ranges from about 216 to 280 nm (π f π*, S 2 r S 0 ), and motion on S 2 is described as a very fast repulsive dissociation. The third band, rarely studied and related to this paper, ranges from 180 to 216 nm and also leads to dissociation of the internal O-N bond. State-resolved studies of NO reveal very different quantum state distributions depending on the photolysis wavelength. For gas-phase irradiation, photodissociation at 35...

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“…Alkyl nitrites in the form R-O-N O have many features such as (1) well-defined chromophore, (2) highly sensitive to light, and (3) relatively simple model heteroatom species [11][12][13] and therefore are taken as the ideal probe to the photolysis reactions. For gas-phase photolysis [14][15][16][17][18][19][20][21][22][23], alkyl nitrite can be dissociated into an alkoxy fragment and NO under UV radiation in the following reaction sequence:…”

Section: Introductionmentioning

confidence: 99%