Electronic structure of the molecular switch tetra-tert-butyl-azobenzene adsorbed on Ag(111)

Tegeder, Petra; Hagen, Sebastian; Leyssner, Felix; Peters, Maike V.; Hecht, Stefan; Klamroth, Tillmann; Saalfrank, Peter; Wolf, Martin

doi:10.1007/s00339-007-4047-0

Cited by 51 publications

(151 citation statements)

References 46 publications

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“…We therefore assign this peak to desorption from the multilayer while the R 2 peaks is associated with desorption from the first monolayer (ML). The thermal desorption behavior of TBS from Au(111) is very similar to those of other aromatic compounds on noble metal surfaces, for example azobenzene derivatives, 11,17,31 benzene, 32,33 hexafluorobenzene, 34 and pyridine, 35 respectively. A common observation in these systems is the substantial broadening of the desorption peak with increasing coverage in the monolayer regime.…”

Section: Resultsmentioning

confidence: 73%

Photoisomerization Ability of Molecular Switches Adsorbed on Au(111): Comparison between Azobenzene and Stilbene Derivatives

et al. 2009

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High resolution electron energy loss spectroscopy and two-photon photoemission was employed to derive the adsorption geometry, electronic structure, and the photoisomerization ability of the molecular switch tetratert-butyl-stilbene (TBS) on Au(111). The results are compared with the azobenzene analogue, tetra-tertbutyl-azobenzene (TBA), adsorbed on Au(111). TBS was found to adsorb on Au(111) in a planar (trans) configuration similar to TBA. The energetic positions of several TBS-induced electronic states were determined, and in comparison to TBA, the higher occupied molecular states (e.g., the highest occupied molecular orbital, HOMO) are located at similar energetic positions. While surface-bound TBA can be switched with light between its trans and cis configurations, in TBS this switching ability is lost. In TBA on Au(111), the trans f cis isomerization is driven by a substrate-mediated charge transfer process, whereby photogenerated hot holes in the Au d band lead to transient positive ion formation (transfer of the holes to the TBA HOMO level). Even though the energetic positions of the HOMOs in TBA and TBS are almost identical and thus a charge transfer should be feasible, this reaction pathway is obviously not efficient to induce the trans f cis isomerization in TBS on Au(111). Quantum chemical calculations of the potential energy surfaces for the free molecules support this conclusion. They show that cation formation facilitates the isomerization for TBA much more pronounced than for TBS due to the larger gradients at the Franck-Condon point and the much smaller barriers on the potential energy surface in the case of the TBA.

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Section: Resultsmentioning

confidence: 73%

Photoisomerization Ability of Molecular Switches Adsorbed on Au(111): Comparison between Azobenzene and Stilbene Derivatives

et al. 2009

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“…3 40 ) has been studied with the femtosecond 2PPE method. [31][32][33][34]41 Specifically, trans-cis isomerization was achieved through UV light exposure. Two-color 2PPE spectra of a 0.9 ML of the TBA-covered Au(111) surface were recorded before and after significant isomerization had taken place, as shown in Fig.…”

Section: Photodesorption Of Ar From Cu(100)mentioning

confidence: 99%

Surface photochemistry probed by two-photon photoemission spectroscopy

Zhou

Ren

et al. 2012

Energy Environ. Sci.

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Two-photon photoemission (2PPE) has been widely used in the study of electronic structure and dynamics of unoccupied electronic states on different types of surfaces and interfaces. Since 2PPE probes electronically excited states, it should be sensitive to surface excited electronic structure changes that accompany surface chemical reactions. Therefore, this method could potentially be used to study the kinetics and dynamics of surface chemical reactions as well as surface photocatalysis. In this article, we briefly review recent progress made in the study of surface photochemistry and photocatalysis using the time-dependent 2PPE (TD-2PPE) method. A few examples are given to demonstrate the application of this method in probing surface photochemistry and photocatalysis, particularly photocatalysis of methanol on TiO 2 surfaces. Since many problems associated with surface photochemistry and surface photocatalysis are related to energy and environmental issues, the 2PPE technique could have important applications in the study of the fundamental problems in energy and environmental sciences.

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“…However, even at these substrates, azobenzene and derivate switches exhibit a host of modifications to the switching function, in all com-binations of reversible or irreversible switching, and switching by light or exclusively by a local electric field. [6][7][8][9] In this situation first-principles calculations stand to offer a unique perspective on the geometric and electronic structure of these systems. With such motivation we have recently performed a density-functional theory ͑DFT͒ study of the metastable states of azobenzene adsorbed at coinage metal ͑111͒ surfaces.…”

Section: Introductionmentioning

confidence: 99%

Azobenzene at coinage metal surfaces: Role of dispersive van der Waals interactions

2009

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We use different semiempirical dispersion correction schemes to assess the role of long-range van der Waals interactions in the adsorption of the prototypical molecular switch azobenzene (C₆H₅-N₂-C₆H₅) at the coinage metal surfaces Cu(111), Ag(111), and Au(111). Compared to preceding density-functional theory results employing a semilocal exchange and correlation functional we obtain partly sizable changes in the computed adsorption geometry and energetics. The discomforting scatter in the results provided by the different schemes is largely attributed to the unknown form of the damping function in the semiempirical correction expression. Using the congeneric problem of the adsorption of benzene as a vehicle to connection with experiment, we cautiously conclude that the account of dispersive interactions at the metal surfaces provided by the various schemes is in the right ballpark, with the more recent, general schemes likely to overbind

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Electronic structure of the molecular switch tetra-tert-butyl-azobenzene adsorbed on Ag(111)

Cited by 51 publications

References 46 publications

Photoisomerization Ability of Molecular Switches Adsorbed on Au(111): Comparison between Azobenzene and Stilbene Derivatives

Photoisomerization Ability of Molecular Switches Adsorbed on Au(111): Comparison between Azobenzene and Stilbene Derivatives

Surface photochemistry probed by two-photon photoemission spectroscopy

Azobenzene at coinage metal surfaces: Role of dispersive van der Waals interactions

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