Photodissociation dynamics of (NO)2 on LiF(001): Characterization of vibrationally excited NO fragments

Jackson, R. C.; Polanyi, J. C.; Sjövall, Peter

doi:10.1063/1.469078

Cited by 25 publications

(17 citation statements)

References 49 publications

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“…34 However, multilayer formation of NO normally occurs at much lower temperatures than the 90 K used in our experiments ͓NO/Ag͑111͒: 15-40 K, 11,34-36 NO/ Pt͑polycryst.͒:Ͼ20 K, 37 NO/LiF͑001͒: 50 K, 38 NO/MgF 2 : 20 K, 39 NO, graphite: 30 K. 40 ͔. Hence, multilayer formation is unlikely the cause of the weakly adsorbed species encountered here.…”

Section: Adsorption Of No: High Coveragesmentioning

confidence: 77%

Ultraviolet-laser induced desorption of NO from the Cr2O3(0001) surface: Involvement of a precursor state?

Wilde

Seiferth

Al‐Shamery

et al. 1999

The Journal of Chemical Physics

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A joint theoretical-experimental investigation of the lower bound states of the NO (X 2 Π)-Ar complex NO molecules interact with the Cr 2 O 3 (0001) surface to form a chemisorption bond of 1.0 eV. At higher coverages an additional more weakly bound species appears in thermal desorption spectra with a binding energy of 0.35 eV. By infrared spectroscopy the weakly adsorbed species is identified to be an unusually strong bound NO-dimer exhibiting a weak feature at 1857 cm Ϫ1 beside the chemisorbate absorption band at 1794 cm Ϫ1 . Laser induced desorption experiments performed at 6.4 eV are presented with main emphasis on the high coverage regime. The desorbing molecules are detected quantum state selectively using resonance enhanced multiphoton ionization. The desorbing molecules are strongly rotationally and vibrationally excited conform with a nonthermal excitation process. The velocity distributions of single rovibronic states of desorbing NO are bimodal and exhibit a strong coupling of rotation and translation. With increasing coverages an additional channel is observed appearing in the time-of-flight spectra of vЉϭ0 as smoothly increasing intensity at long flight times. The numeric values of these unusually long flight times are indicative for long residence times on the surface rather than small kinetic energies. The desorption efficiencies weakly depend on the concentration and vibrational state ranging from (2.0Ϯ0.3)ϫ10 Ϫ17 cm 2 at low coverages to (1.0Ϯ0.4)ϫ10 Ϫ17 cm 2 at high coverages for vЉϭ0. The intensity of the desorption signal per laser pulse only increases proportional to the chemisorbate coverage. The data are interpreted assuming the dimers to act as extrinsic precursors within the desorption process.

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Section: Adsorption Of No: High Coveragesmentioning

confidence: 77%

Ultraviolet-laser induced desorption of NO from the Cr2O3(0001) surface: Involvement of a precursor state?

Wilde

Seiferth

Al‐Shamery

et al. 1999

The Journal of Chemical Physics

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“…This suggests that the new mechanism could be creation of a transient positive adsorbate ion (TPI) by tunneling of an electron from the highest occupied molecular orbital (HOMO) of the adsorbate into a surface d-hole. 32 Calculational effort to obtain states and PESs concerned would be highly desirable; the detailed data of the DOF energy distributions would be good points of comparison. 13; a similar suggestion has been made recently for a more complex surface photochemical reaction.…”

Section: B the Regime Of High Excitation Energy And Small Particlesmentioning

confidence: 99%

State-resolved investigation of the photodesorption dynamics of NO from (NO)2 on Ag nanoparticles of various sizes in comparison with Ag(111)

Mulugeta¹,

Watanabe²,

Menzel³

et al. 2011

The Journal of Chemical Physics

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The translational and internal state energy distributions of NO desorbed by laser light (2.3, 3.5, and 4.7 eV) from adsorbed (NO)(2) on Ag nanoparticles (NPs) (mean diameters, D = 4, 8, and 11 nm) have been investigated by the (1 + 1) resonance enhanced multiphoton ionization technique. For comparison, the same experiments have also been carried out on Ag(111). Detected NO molecules are hyperthermally fast and both rotationally and vibrationally hot, with temperatures well above the sample temperature. The translational and rotational excitations are positively correlated, while the vibrational excitation is decoupled from the other two degrees of freedom. Most of the energy content of the desorbing NO is contained in its translation. The translational and internal energy distributions of NO molecules photodesorbed by 2.3, 3.5, and in part also 4.7 eV light are approximately constant as a function of Ag NPs sizes, and they are the same on Ag(111). This suggests that for these excitations a common mechanism is operative on the bulk single crystal and on NPs, independent of the size regime. Notably, despite the strongly enhanced cross section seen on NP at 3.5 eV excitation energy in p-polarization, i.e., in resonance with the plasmon excitation, the mechanism is also unchanged. At 4.7 eV and for small particles, however, an additional desorption channel is observed which results in desorbates with higher energies in all degrees of freedom. The results are well compatible with our earlier measurements of size-dependent translational energy distributions. We suggest that the broadly constant mechanism over most of the investigated range runs via a transient negative ion state, while at high excitation energy and for small particles the transient state is suggested to be a positive ion.

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“…Since the adsorption bond of ðNOÞ 2 on Ag most likely involves some hybridization of Ag d electrons with dimer a 1 states [28], production of holes in these d states at the surface could lead to a transient positive ion (TPI). These holes, created throughout the NP, must become localized at the surface to be able to ionize the adsorbate hybrid.…”

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confidence: 99%

Size Effects in Thermal and Photochemistry of(NO)2on Ag Nanoparticles

et al. 2008

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NO dimers adsorbed on alumina supported silver nanoparticles (Ag NPs, radii R approximately 1-6 nm) show decreasing desorption temperatures and complex behavior of photoinduced desorption with decreasing NP size. In particular, for resonant excitation of the (1,0) Mie plasmon at 3.5 eV the photoinduced desorption cross section increases with 1/R, showing a pronounced enhancement (40 times) at R approximately 2.5 nm compared to Ag(111). At 4.7 eV the translational temperature of photodesorbed NO increases strongly with 1/R. We discuss these trends and peculiarities in terms of the size-dependent properties of the Ag NPs.

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Photodissociation dynamics of (NO)2 on LiF(001): Characterization of vibrationally excited NO fragments

Cited by 25 publications

References 49 publications

Ultraviolet-laser induced desorption of NO from the Cr2O3(0001) surface: Involvement of a precursor state?

Ultraviolet-laser induced desorption of NO from the Cr2O3(0001) surface: Involvement of a precursor state?

State-resolved investigation of the photodesorption dynamics of NO from (NO)2 on Ag nanoparticles of various sizes in comparison with Ag(111)

Size Effects in Thermal and Photochemistry of(NO)2on Ag Nanoparticles

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