A novel system-bath Hamiltonian for vibration-phonon coupling: Formulation, and application to the relaxation of Si–H and Si–D bending modes of H/D:Si(100)-(2 × 1)

Lorenz, Ulf; Saalfrank, Peter

doi:10.1016/j.chemphys.2016.06.004

Cited by 8 publications

(10 citation statements)

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“…The D:Si(100) Adsorbate-Surface Model Here, we briefly review the main aspects of the quantum mechanical / molecular mechanics (QM/MM) embedded cluster model 11 used in this work and in Refs. [10][11][12][13] .…”

Section: Model and Methodsmentioning

confidence: 99%

“…For this cluster, a normal mode analysis was performed and for one of the D-Si-Si modes, called "⊥, a" (perpendicular, asymmetric) in Ref. 11 , an anharmonic potential V (q) was computed along the corresponding normal mode coordinate, q. We then solved the corresponding stationary vibrational Schrödinger equation on a set of discrete grid points to obtain the vibrational eigenpairs {ε v , |v }.…”

Section: Model and Methodsmentioning

confidence: 99%

“…For D:Si(100)-(2×1), based on quantum chemical calculations, a realistic model Hamiltonian has been devised in Ref. 11 , comprising an anharmonic system mode non-linearly coupled to more than 2000 surface oscillators ("phonons"). This model has been used in previous work to study the multi-dimensional quantum dynamics typical for an "open system" 10,12,13 and will be applied here also, for additional aspects not covered previously.…”

Section: Introductionmentioning

confidence: 99%

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Non-Markovian Vibrational Relaxation Dynamics at Surfaces

Fischer,

Werther,

Bouakline

et al. 2022

Preprint

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Section: Model and Methodsmentioning

confidence: 99%

Section: Model and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Non-Markovian Vibrational Relaxation Dynamics at Surfaces

Fischer,

Werther,

Bouakline

et al. 2022

Preprint

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“…Understanding the vibrations of adsorbates at surfaces and their relaxation is important for many applications in chemistry and physics [34,35]. Molecules adsorbed on metal surfaces may couple to electron-hole pairs of the surface and their non-radiative vibrational lifetimes are often in the ps range or even shorter due to vibrationelectron coupling [35][36][37].…”

mentioning

confidence: 99%

“…Molecules adsorbed on metal surfaces may couple to electron-hole pairs of the surface and their non-radiative vibrational lifetimes are often in the ps range or even shorter due to vibrationelectron coupling [35][36][37]. The lifetime of vibrations of adsorbates can be rather short (ns to sub-ps) also due to vibration-phonon coupling, in particular, when the vibration lies within the phonon band of the surface [34,38].…”

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confidence: 99%

Efficient non-resonant intermolecular vibrational energy transfer

Cederbaum

2018

Molecular Physics

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Molecular excited vibrational states are metastable states and we incorporate their finite lifetimes into the theory of vibrational energy transfer between weakly interacting molecules, i.e., at internuclear distances at which they do not have a chemical bond. Expressions for the effective lifetime of an initially vibrationally excited molecule in the presence of a neighboring molecule are derived in closed form. These expressions allow one to analyze the physics behind the energy transfer. It is shown that due to different finite lifetimes of the isolated excited molecules, a very efficient vibrational energy transfer can take place between them even if their energies are rather off-resonance. Examples are discussed.Vibrations constitute a fundamental property of molecules and of other matter made of molecules. Excited vibrational molecular levels in the electronic ground state decay rather slowly radiatively, their radiative lifetime is typically in the range of seconds to milliseconds [1], see also [2]. In contrast, fast non-radiative lifetimes in the range of pico-and even femtoseconds have been reported for even small polyatomic molecules [3][4][5]. The underlying mechanism of intramolecular vibrational energy redistribution (IVR) has attracted much attention for several decades [3][4][5][6][7][8]. Here, an optically active vibrational mode couples to other modes which in turn couple to other modes (tier model [5,9]) redistributing the energy of the initially excited mode over other parts of the molecule. Anharmonic coupling plays here a decisive role. We shall return to the IVR below.The presence of IVR suggests the investigation of the more general subject of vibrational energy flow in molecules which has become an active field of research (for a recent review see [10]). Multidimensional spectroscopy experiments and theoretical investigations provide valuable information on this flow and hence on vibrational energy transport (or transfer) in condensed phase molecular systems, see, e.g., [11][12][13][14][15] and references therein. The major driving force of vibrational energy transfer is again anharmonicity [14][15][16].In this work we investigate the possibility for vibrational energy transfer between weakly interacting molecules, i.e., between molecules at distances where chemical bonds are not formed. We show that indeed such a transfer can be efficient even if it is not resonant, i.e., the respective levels are rather far from matching. The main ingredient is that the participating vibrational excited levels are metastable states of finite lifetimes. These lifetimes can be due to radiative decay, IVR or any other kind of decay, like predissociation. Consider a molecule 1 with a vibrational state of complex energy E 1 − iΓ 1 /2 which interacts with a vibrational state of a neighboring molecule 2 of complex energy E 2 − iΓ 2 /2, where Γ is the width of a level of lifetime τ = /Γ [17,18]. The time-evolution of the coupled metastable states (also called resonances) is governed by the Schroedinger equa-wher...

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