Supersonic Molecular Beams Studies of Surfaces

Vattuone, L.; Bracco, G.; Smerieri, Marco; Savio, Letizia; Rocca, M.

doi:10.1007/978-3-642-32955-5_1

Cited by 4 publications

(4 citation statements)

References 89 publications

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“…Progress toward this direction has been possible by combining supersonic molecular beams (SMBs) , and reflection absorption infrared spectroscopy (RAIRS) experiments. , In contrast to techniques that can only measure the site-averaged reactivities, such a combination has recently allowed measurement of site-specific reactive sticking probabilities of methane on stepped Pt surfaces. − Moreover, using laser techniques to vibrationally excite partially deuterated methane molecules, it has been possible to achieve full site and bond selectivity. , Such an achievement has been considered as a dissection of a chemical reaction on a metal surface . Opening that sort of doors drives us to important discoveries but, in general, also brings to light new intriguing issues.…”

Section: Introductionmentioning

confidence: 99%

Site-Specific Product Selectivity of Stepped Pt Surfaces for Methane Dehydrogenation

Torio

Busnengo

2020

J. Phys. Chem. C

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Through density functional theory (DFT) calculations, we show that, in contrast to terrace sites of Pt(211) and Pt(111), on steplike sites of Pt(211) and Pt(110)-(2 × 1), methylene is more stable than methyl. The resulting site-dependent product selectivity for methane dissociation allows us to conciliate between theory and recent reflection absorption infrared spectroscopy (RAIRS) experiments, which might open a door to new applications of vicinal surfaces of Pt in heterogeneous catalysis and as templates for nanoscale patterning of self-assembled monolayers.

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Section: Introductionmentioning

confidence: 99%

Site-Specific Product Selectivity of Stepped Pt Surfaces for Methane Dehydrogenation

Torio

Busnengo

2020

J. Phys. Chem. C

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“…Supersonic molecular beam techniques at low-index single crystal surfaces have made an unequivocal contribution in this respect, providing sticking coefficient data for a wide range of well-defined initial conditions of incidence energy and angle, as well as resolved rotational or vibrational state. 3 In terms of dissociative adsorption, corresponding data have been traditionally analyzed to distinguish regimes of a) Electronic mail: vanessa.bukas@ch.tum.de direct or indirect adsorption. 4 The former essentially suggests immediate dissociation upon impact with the surface.…”

Section: Introductionmentioning

confidence: 99%

Fingerprints of energy dissipation for exothermic surface chemical reactions: O2 on Pd(100)

Bukas

Mitra

Meyer

et al. 2015

The Journal of Chemical Physics

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We present first-principles calculations of the sticking coefficient of O 2 at Pd(100) to assess the effect of phononic energy dissipation on this kinetic parameter. For this we augment dynamical simulations on sixdimensional potential energy surfaces (PESs) representing the molecular degrees of freedom with various effective accounts of surface mobility. In comparison to the prevalent frozen-surface approach energy dissipation is found to qualitatively affect the calculated sticking curves. At the level of a generalized Langevin oscillator (GLO) model we achieve good agreement with experimental data. The agreement is similarly reached for PESs based on two different semi-local density-functional theory functionals. This robustness of the simulated sticking curve does not extend to the underlying adsorption mechanism, which is predominantly directly dissociative for one functional or molecularly trapped for the other. Completely different adsorption mechanisms therewith lead to rather similar sticking curves that agree equally well with the experimental data. This highlights the danger of the prevalent practice to extract corresponding mechanistic details from simple fingerprints of measured sticking data for such exothermic surface reactions.

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“…For the ensemble of gas-phase molecules in a molecular beam, another central experimentally accessible kinetic quantity is the (initial) sticking coefficient, i.e. the fraction of molecules that has lost sufficient energy to remain adsorbed at the surface [22]. The latter is usually a function of several variables such as beam incidence energy and angle, substrate temperature and specifically prepared rotational and vibrational quantum state of the impinging molecules [23].…”

Section: Inelastic Scattering and Adsorptionmentioning

confidence: 99%

Energy dissipation at metal surfaces

Rittmeyer

Bukas

Reuter

2017

Advances in Physics: X

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Conversion of energy at the gas-solid interface lies at the heart of many industrial applications such as heterogeneous catalysis. Dissipation of parts of this energy into the substrate bulk drives the thermalization of surface species, but also constitutes a potentially unwanted loss channel. At present, little is known about the underlying microscopic dissipation mechanisms and their (relative) efficiency. At metal surfaces, prominent such mechanisms are the generation of substrate phonons and the electronically non-adiabatic excitation of electron-hole pairs. In recent years, dedicated surface science experiments at defined single-crystal surfaces and predictive-quality firstprinciples simulations have increasingly been used to analyze these dissipation mechanisms in prototypical surface dynamical processes such as gas-phase scattering and adsorption, diffusion, vibration, and surface reactions. In this topical review we provide an overview of modeling approaches to incorporate dissipation into corresponding dynamical simulations starting from coarsegrained effective theories to increasingly sophisticated methods. We illustrate these at the level of individual elementary processes through applications found in the literature, while specifically highlighting the persisting difficulty of gauging their performance based on experimentally accessible observables.

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Supersonic Molecular Beams Studies of Surfaces

Cited by 4 publications

References 89 publications

Site-Specific Product Selectivity of Stepped Pt Surfaces for Methane Dehydrogenation

Site-Specific Product Selectivity of Stepped Pt Surfaces for Methane Dehydrogenation

Fingerprints of energy dissipation for exothermic surface chemical reactions: O2 on Pd(100)

Energy dissipation at metal surfaces

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