Unoccupied molecular orbitals of aromatic hydrocarbons adsorbed on Ag(111)

Frank, K. H.; Yannoulis, P.; Dudde, R.; Koch, E. E.

doi:10.1063/1.455720

Cited by 115 publications

(92 citation statements)

References 35 publications

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“…Experimental studies have reported that both anthracene and pentacene monolayers weakly adsorb on Ag(111), as characteristic of physisorption or weak chemisorption [5][6][7][8][9][10] , which suggests that van der Waals interactions (vdW) play an important role in the binding of these systems.…”

Section: Introductionmentioning

confidence: 99%

The role of the van der Waals interactions in the adsorption of anthracene and pentacene on the Ag(111) surface

Morbec

Kratzer

2017

The Journal of Chemical Physics

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Using first-principles calculations based on density-functional theory (DFT) we investigated the effects of the van der Waals (vdW) interactions on the structural and electronic properties of anthracene and pentacene adsorbed on the Ag(111) surface. We found that the inclusion of vdW corrections strongly affects the binding of both anthracene/Ag(111) and pentacene/Ag(111), yielding adsorption heights and energies more consistent with the experimental results than standard DFT calculations with generalized gradient approximation (GGA). For anthracene/Ag(111) the effect of the vdW interactions is even more dramatic: we found that "pure" DFT-GGA calculations (without including vdW corrections) result in preference for a tilted configuration, in contrast to experimental observations of flat-lying adsorption; including vdW corrections, on the other hand, alters the binding geometry of anthracene/Ag(111), favoring the flat configuration. The electronic structure obtained using a self-consistent vdW scheme was found to be nearly indistinguishable from the conventional DFT electronic structure once the correct vdW geometry is employed for these physisorbed systems. Moreover, we show that a vdW correction scheme based on a hybrid functional DFT calculation (HSE) results in an improved description of the highest occupied molecular level of the adsorbed molecules.

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Section: Introductionmentioning

confidence: 99%

The role of the van der Waals interactions in the adsorption of anthracene and pentacene on the Ag(111) surface

Morbec

Kratzer

2017

The Journal of Chemical Physics

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“…1 Yet the available experimental data on this interface is limited. 1,10,[33][34][35] The emphasis in the present study is placed on structural data collected with scanning tunneling microscopy (STM) and low energy electron diffraction (LEED); in particular we present a refined phase diagram of the Tc/Ag(111) interface in the coverage range 0 to 2.4 MLs. Based on the structural data presented here, electronic structure studies, 35 kinetic growth studies, etc., may be performed in the future.…”

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confidence: 99%

Structure and growth of tetracene on Ag(111)

et al. 2011

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The structure of the tetracene/Ag(111) interface in the coverage range θ = 0 to 2.4 ML is studied with scanning tunneling microscopy (STM) at 8 K and with low energy electron diffraction (LEED) at T = 300 . . . 100 K. For θ 0.01 ML, one-dimensional (1D) diffusion of single molecules along 011 -directions is observed even at 8 K. For 0.1 ML < θ < 0.5 ML molecules are homogeneously distributed over the surface forming a disordered phase (static at T = 8 K, dynamic at T = 25 K), indicating a repulsive intermolecular interaction (δ-phase). For θ 0.5 ML, local ordering in the commensurate γ -phase is observed. Further increase of the coverage yields a compressed monolayer (ML) phase (θ ≡ 1 ML) with point-on-line registry (α-phase). The interaction between molecules has been calculated with the force-field approach to rationalize the molecular packing motifs in the various phases. Under most circumstances molecule-molecule interactions are repulsive, in agreement with experimental findings. A simulation of the adsorption up to θ = 1 ML according to the random sequential adsorption (RSA) algorithm shows that the disorder-to-order transition from the δ-to γ -phase occurs close to random close packing (RCP), θ = 0.5-0.6 ML. Since tetracene molecules are a two-dimensional (2D) representation of Onsager's hard rod model, this suggests that this phase transition is driven both energetically and entropically. For θ ≈ 2.23 ML a metastable bilayer phase with point-on-line coincidence is observed (β-phase). The basic structural unit of this phase is a triplet of molecules that are tilted along the long molecular axis against each other; at least one of these molecules is tilted out of the surface plane. Within the β-phase a superstructure of alternating rotation domains is observed. This superstructure has a period of 7.4 nm. The molecular packing in the β-phase resembles the packing in the bulk crystal structure of tetracene, its formation can therefore be interpreted as incipient pseudomorphic growth of tetracene on Ag(111). However, pseudomorphic growth cannot be continued beyond the β-phase.

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“…130,131 On the basis of these data, the E LUMO value was estimated to be À0:86 eV for Nph single crystal. In addition, in the experimental results of IPES for highly ordered Nph thin film on Ag(111) reported by Frank et al, 123 the energy of the LUMO from the vacuum level has been reported to be À1:1 AE 0:15 eV. Because of image charges on the metal substrate, this energy may be a little larger than the intrinsic energy of the bulk.…”

Section: Insight Into Isomers: Comparison To the Bulkmentioning

confidence: 94%

“…122 In strong contrast, there are rather few reliable experimental data for P À , while it is currently under investigation by means of inverse photoemission spectroscopy (IPES). [123][124][125][126] Finite-size cluster anions of -conjugated molecules are viewed as an embryo of a negative polaron in organic molecular solids, because the single excess electron doped in the cluster is stabilized by the finite number of polarized molecules, i.e., a finite-size polarization cloud. As shown in Fig.…”

Section: Research Backgroundmentioning

confidence: 99%

Formation of Large Molecular Cluster Anions and Elucidation of Their Electronic Structures

Mitsui¹,

Nakajima²

2007

Bulletin of the Chemical Society of Japan

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The present account describes our efforts to understand the microscopic aspects of condense phase phenomena, such as ion solvation in molecular liquids and charge carrier localization in molecular solids, by viewing finite-size molecular clusters as their embryonic forms. In this effort, we efficiently prepared supersonically cooled, isolated molecular cluster anions with up to more than 100 constituent molecules and size-selectively investigated their electronic structures using anion photoelectron spectroscopy. Large anionic clusters of two different types of organic molecule; acetonitrile and naphthalene reported as examples of the noteworthy results obtained in our studies. In these two systems, we found that energetically close anionic isomers coexist over a broad range in size, and their contribution in the photoelectron spectra could be separated using anion beam hole-burning technique. A detailed inspection into the electronic states and size-dependent energetics of each isomer has enabled us to establish a link from the large finite cluster to the infinite bulk system. Molecular clusters are finite aggregates consisting of 2-10 4 molecules and have been regarded as an excellent model system to use for gaining profound insights into weak noncovalent interactions, which play a predominant role in determining the structures and properties of molecular assemblies in chemistry, biology, and soft-material science. In molecular clusters, most of the properties originate from weakly perturbed, easily recognized, and well-defined units. Additionally, the finite number of molecules in the gas phase under collisionfree conditions makes a theoretical treatment much easier than that of bulk liquids and solids. Over the last two decades, therefore, intensive experimental and theoretical studies on molecular clusters have been performed, and a large number of review articles on the spectroscopic study of molecular clusters have been published in last twenty years.

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Unoccupied molecular orbitals of aromatic hydrocarbons adsorbed on Ag(111)

Cited by 115 publications

References 35 publications

The role of the van der Waals interactions in the adsorption of anthracene and pentacene on the Ag(111) surface

The role of the van der Waals interactions in the adsorption of anthracene and pentacene on the Ag(111) surface

Structure and growth of tetracene on Ag(111)

Formation of Large Molecular Cluster Anions and Elucidation of Their Electronic Structures

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