Femtosecond ultraviolet laser-induced desorption of NO from NiO(100)/Ni(100)

Eichhorn, G.; Richter, M.; Al‐Shamery, Katharina; Zacharias, H.

doi:10.1063/1.479281

Cited by 30 publications

(28 citation statements)

References 70 publications

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“…In particular, a microscopic description of the dissipation has not been attempted so far. We therefore combine the information from previous studies 4,11,39,40,42,43 with the surrogate Hamiltonian method 2,3 to develop a model which treats the nuclear dynamics as well as the excitation and relaxation mechanism on the same level of rigor.…”

Section: Introductionmentioning

confidence: 99%

Surrogate Hamiltonian study of electronic relaxation in the femtosecond laser induced desorption of NO/NiO(100)

Koch

Klüner

Freund

et al. 2003

The Journal of Chemical Physics

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Electronic relaxation and ion desorption processes of solid Si(CH 3 ) 2 Cl 2 following Si 2p core-level excitation J. Chem. Phys. 106, 9105 (1997); 10.1063/1.474016 Two-dimensional wave packet studies of photon-stimulated desorption of NO from a metal surface induced by single and multiple electronic excitations A microscopic model for electronic quenching in the photodesorption of NO from NiO͑100͒ is developed. The quenching is caused by the interaction of the excited adsorbate-substrate complex with electron hole pairs (O 2p→Ni 3d states͒ in the surface. The electron hole pairs are described as a bath of two level systems which are characterized by an excitation energy and a dipole charge. The parameters are connected to estimates from photoemission spectroscopy and configuration interaction calculations. Due to the localized electronic structure of NiO a direct optical excitation mechanism can be assumed, and a reliable potential energy surface for the excited state is available. Thus a treatment of all steps in the photodesorption event from first principles becomes possible for the first time. The surrogate Hamiltonian method, which allows one to monitor convergence, is employed to calculate the desorption dynamics. Desorption probabilities of the right order of magnitude and velocities in the experimentally observed range are obtained.

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Section: Introductionmentioning

confidence: 99%

Surrogate Hamiltonian study of electronic relaxation in the femtosecond laser induced desorption of NO/NiO(100)

Koch

Klüner

Freund

et al. 2003

The Journal of Chemical Physics

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“…2 a 3 transition in the CO molecule in gas phase, as the crucial excitation step in laser-induced desorption [14]. This is in contrast to the NO-NiO(100) system, where a charge transfer state, resulting in an NO ÿ -NiO species, is the decisive excited state [1] in similar photoinduced desorption experiments [15,16]. To verify whether a 5 !…”

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confidence: 98%

Understanding Surface Photochemistry from First Principles: The Case of CO-NiO(100)

Mehdaoui

Klüner

2007

Phys. Rev. Lett.

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The excitation mechanism in the CO-NiO(100) system induced by a uv-laser pulse has been investigated from first principles. For the laser-driven process, the relevant electronically excited states are identified, and it is shown that a transition within the CO molecule is the crucial excitation step rather than substrate mediated processes. A new mechanism is proposed, in which the formation of a genuine C-Ni bond in the excited state is the driving force for photodesorption rather than electrostatic interactions, as has been found in similar systems. This results in very high velocities of CO molecules desorbing from the NiO(100) surface after electronic relaxation.

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“…Fig. 3) are found to be in the experimentally observed range between 0 and 2000 m=s [8,9]. Up to 21 layers with N 51 and up to 13 layers with N 101 bath modes in each layer were considered.…”

Section: P H Y S I C a L R E V I E W L E T T E R S Week Ending 21 Marmentioning

confidence: 99%

“…This argument is supported by the experimental finding that state resolved velocity distributions are independent of the laser energy h! L [8].…”

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confidence: 99%

“…A particularly well studied example where quenching by electron-hole pairs in an insulator surface is crucial is given by the laser-induced desorption of NO from NiO(100). We have therefore combined information from previous experimental [8,9] and theoretical [2,10] studies with the surrogate Hamiltonian method to develop a model which treats all steps of the DIET dynamics on the same level of rigor. The method is, however, of general applicability and has been employed to metal surfaces [6] and chromophores in solution [7] before.…”

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confidence: 99%

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Femtosecond Photodesorption of Small Molecules from Surfaces: A Theoretical Investigation from First Principles

et al. 2003

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A microscopic model for the excitation and relaxation processes in photochemistry at surfaces is developed. Our study is based on ab initio calculations and the surrogate Hamiltonian method treating surface electron-hole pairs as a bath of two-level systems. Desorption probabilities and velocities in the experimentally observed range are obtained. The excited state lifetime is calculated, and a dependence of observables on pulse length is predicted. DOI: 10.1103/PhysRevLett.90.117601 PACS numbers: 79.20.La, 68.43.Tj Surface photochemistry occurs in many instances, including photocatalysis, atmospheric chemistry, and photochemical reactions at interstellar dust particles. Despite its ubiquitous nature, a microscropic understanding of the underlying basic processes remains a great challenge. In order to obtain a detailed mechanistic picture, the complexity of the studied systems and processes has to be reduced significantly. The simplest photochemical phenomenon on surfaces is laser-induced desorption of small molecules. Two-state models such as the Menzel-GomerRedhead or Antoniewicz scenarios [1] have proven useful to qualitatively understand the mechanism of DIET (desorption induced by electronic transitions). In both models, the excitation from the electronic ground to an excited state and the relaxation back to the ground state are modeled as vertical transitions. While significant progress has recently been made concerning reliable potential energy surfaces for DIET dynamics [2,3], excitation and relaxation mechanisms have been modeled only semiphenomenologically [4,5] assuming a separation of time scales of excitation, excited state nuclear dynamics, and quenching. Since electronic relaxation occurs on the time scale of femtoseconds [5], this assumption breaks down with the introduction of femtosecond laser pulses.Electronic relaxation is caused by the interaction of the excited adsorbate-substrate complex with electron-hole pairs in the surface [5]. In this Letter, we develop a microscopic model for this interaction assuming that electron-hole pairs can be described as a bath of twolevel systems (TLS). The surrogate Hamiltonian approach [6] is employed in which for a finite time the infinitely many TLS are approximated by a finite number. The finite time interval for which converged results can be obtained depends on the interaction strength and the number of TLS. This means that convergence is controllable and no further assumptions are needed. The surrogate Hamiltonian approach represents one possibility to treat a quantum system interacting with its environment.Since it does not rely on the approximation of weak coupling between system and environment and a separation of time scales of system dynamics and relaxation, it is particularly well suited to describe ultrafast charge transfer events in condensed phase [7]. In the present study, the construction of the bath is tailored to model electron-hole pairs in insulator and semiconductor surfaces. A particularly well studied example where quenching by ...

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Femtosecond ultraviolet laser-induced desorption of NO from NiO(100)/Ni(100)

Cited by 30 publications

References 70 publications

Surrogate Hamiltonian study of electronic relaxation in the femtosecond laser induced desorption of NO/NiO(100)

Surrogate Hamiltonian study of electronic relaxation in the femtosecond laser induced desorption of NO/NiO(100)

Understanding Surface Photochemistry from First Principles: The Case of CO-NiO(100)

Femtosecond Photodesorption of Small Molecules from Surfaces: A Theoretical Investigation from First Principles

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