Photochemistry of acetylene physisorbed on sodium chloride: a temperature-dependent hydrogen-exchange reaction

Dunn, Seth; Ewing, George E.

doi:10.1021/j100132a031

Cited by 10 publications

(7 citation statements)

References 14 publications

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“…The photochemistry of molecules adsorbed onto such films has been studied, yielding a variety of results. Dunn and Ewing observed that energy transfer from a triplet self-trapped exciton in NaCl crystallites may be efficiently transferred to a near-resonant triplet state of adsorbed acetylene . Berg and Ewing found that ketene's photodissociation may be enhanced or quenched upon adsorption, depending on the electronic state into which the molecule is excited .…”

Section: Introductionmentioning

confidence: 99%

Spectra and Photochemistry of Trifluoronitrosomethane Adsorbed on Alkali Halide Films

et al. 1996

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Trifluoronitrosomethane (CF 3 NO), which is readily photolyzed in the gas phase when exposed to light in the 600-700 nm portion of the spectrum, does not undergo significant photolysis when irradiated while adsorbed on sublimated films of alkali halides (NaCl, NaBr, KCl, KBr) at temperatures of 10-100 K. This quenching does not occur when the molecule is irradiated while adsorbed on argon films (thickness > 0.1 µm) or in multilayer coverage. Comparison of the quantum efficiencies for photolysis indicates that vibrational relaxation induced by surface phonons is primarily responsible for the alkali halide quenching, but lateral diffusion of the photofragments and/or excited-state molecules may also play a role in the kinetic scheme. The photochemistry was followed using infrared spectroscopy, providing the first vibrational characterization of adsorbed sub-monolayer CF 3 NO. A photodimer of CF 3 NO was also observed and vibrationally characterized on the argon films and on the overlayers. The NO stretching frequency for the dimer is significantly lower than had been previously reported for the N-nitritoamine photodimer {(CF 3 ) 2 NONO} and may indicate the existence of a second photodimer species. Adsorption potentials were calculated for various sites on the four alkali halide films. The lowest energy orientation in each case had the C-N bond parallel to the surface, aligned in the [110] direction. The vibrational spectra and thermal desorption curves are consistent with the calculated energies.

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Section: Introductionmentioning

confidence: 99%

Spectra and Photochemistry of Trifluoronitrosomethane Adsorbed on Alkali Halide Films

et al. 1996

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“…In a recent series of papers, − Dunn and Ewing described the photochemical reactivity of acetylene adsorbed on NaCl(100) monocrystals or crystallites. These authors observed an intermolecular proton exchange after UV irradiation, which was evidenced by isotopic substitution: This proton exchange can be explained by photodimerization or by the breaking of the chemical bond in the acetylene molecule.…”

Section: Introductionmentioning

confidence: 99%

“…In a recent series of papers, [2][3][4][5][6][7] Dunn and Ewing described the photochemical reactivity of acetylene adsorbed on NaCl-(100) monocrystals or crystallites. These authors observed an intermolecular proton exchange after UV irradiation, which was evidenced by isotopic substitution:…”

Section: Introductionmentioning

confidence: 99%

Quantum ab Initio Study of Acetylene Adsorption on NaCl(100). II. Excited States and Photochemistry

Allouche

1996

J. Phys. Chem.

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The photochemistry of acetylene adsorbed on NaCl(100) was modeled using the unrestricted Hartree-Fock method for the ground state and the CI-single method for the electronic excited states. After comparison of the results from the CI-single method with those of previous work, a number of reactive processes were studied, including the cycloaddition of two adsorbed molecules, one of which is situated in the first excited triplet state, the dissociation of the triplet state adsorbed on the perfect surface, and the dissociation of C 2 H 2 adsorbed on a surface defect in ground or triplet state. The intermediate stationary states of the photolysis have been identified. The results are compared with experimental results.

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“…Adsorption processes in particular, i.e., the sticking of the molecules at the interface over a sufficiently long time, have become an important field of research during the past decades. [4][5][6][7][8][9] By means of infrared ͑IR͒ spectroscopy, Dunn and Ewing have studied the adsorption of acetylene molecules on well-defined NaCl͑100͒ single-crystal cleavage planes at cryogenic temperatures and uhv conditions. Acetylene, on the other hand, is a trace gas originating from combustion processes with lifetimes in the atmosphere of several days.…”

Section: Introductionmentioning

confidence: 99%

Structure and infrared absorption of the first layer C2H2 on the NaCl(100) single-crystal surface

Cabello-Cartagena

Vogt

Weiß

2010

The Journal of Chemical Physics

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The adsorbate structure of the first layer acetylene on the NaCl(100) single-crystal surface is investigated using polarization infrared spectroscopy in combination with low-energy electron diffraction (LEED) experiments, and potential calculations on the basis of pair potentials. In agreement with a previous study, a triplet of infrared absorptions in the region of the asymmetric stretch vibration of C(2)H(2) was observed and assigned to an adsorbate phase with (3 square root 2 x square root 2)R45 degrees translational symmetry determined in the LEED experiment. The polarization dependence of the infrared spectra is consistent with a parallel orientation of the molecules with respect to the surface. The number of molecules per unit cell is four to six as determined by photometric considerations. Total energy minimizations support a new structure model which contains five inequivalent molecules per unit cell in a herringbone arrangement. The application of a vibrational exciton approach demonstrates that this new structure model can reproduce the triplet spectrum observed in the infrared experiments.

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Photochemistry of acetylene physisorbed on sodium chloride: a temperature-dependent hydrogen-exchange reaction

Cited by 10 publications

References 14 publications

Spectra and Photochemistry of Trifluoronitrosomethane Adsorbed on Alkali Halide Films

Spectra and Photochemistry of Trifluoronitrosomethane Adsorbed on Alkali Halide Films

Quantum ab Initio Study of Acetylene Adsorption on NaCl(100). II. Excited States and Photochemistry

Structure and infrared absorption of the first layer C2H2 on the NaCl(100) single-crystal surface

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