UPS measurements of molecular energy level of condensed gases

Yu, Kaifu; McMenamin, J. C.; Spicer, W. E.

doi:10.1016/0039-6028(75)90179-x

Cited by 80 publications

(16 citation statements)

References 10 publications

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“…The relaxation energies are larger than the value observed for condensed benzene layers (1.0-1.4 eV [321][322][323]). Representative of them, Fig.…”

Section: Electronic Structure Of Adsorbates (I) Work Function Changecontrasting

confidence: 61%

“…The direction of these extra shifts of the ∆E π is opposite to that of the relaxation shifts, and they result from bonding interactions between the π-orbitals in the condensed phase. For condensed benzene layers, such interactions have not been observed by photoemission spectroscopy [321,322].…”

Section: Electronic Structure Of Adsorbates (I) Work Function Changementioning

confidence: 99%

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Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

Weiß

Ranke

2002

Progress in Surface Science

584

610

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Metal-oxide based catalysts are used for many important synthesis reactions in the chemical industry. A better understanding of the catalyst operation can be achieved by studying elemantary reaction steps on well-defined model catalyst systems. For the dehydrogenation of ethylbenzene to styrene in the presence of steam both unpromoted and potassium promoted iron-oxide catalysts are active. Here we review the work done over unpromoted single-crystalline FeO(111), Fe 3 O 4 (111) and α-Fe 2 O 3 (0001) films grown epitaxially on Pt(111) substrates. Their geometric and electronic surface structures were characterized by STM, LEED, electron microscopy and electron spectroscopic techniques. In an integrative approach, the interaction of water, ethylbenzene and styrene with these films was investigated mainly by thermal desorption and photoelectron emission spectroscopy. The adsorptiondesorption energetics and kinetics depend on the oxide surface terminations and are correlated to the electronic structures and acid-base properties of the corresponding oxide phases, which reveal insight into the nature of the active sites and into the catalytic function of semiconducting oxides in general. Catalytic studies, using a batch reactor arrangement at high gas pressures and post reaction surface analysis, showed that only α-Fe 2 O 3 (0001) containing surface defects is catalytically active, whereas Fe 3 O 4 (111) is always inactive. This can be related to the elementary adsorption and desorption properties observed in ultrahigh vacuum, which indicates that the surface chemical properties of the iron-oxide films do not change significantly across the "pressure-gap". A model is proposed according to which the active site involves a regular acidic surface sites and a defect site next to it. The results on metal-oxide surface chemistry also have implications for other fields, such as environmental science, biophysics and chemical sensors.-2 -"2kyEi9FYSQjBVrZxIPQ.FHIAC_WRa02_review.doc", Datum: 19.02.03

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“…The relaxation energies are larger than the value observed for condensed benzene layers (1.0-1.4 eV [321][322][323]). Representative of them, Fig.…”

Section: Electronic Structure Of Adsorbates (I) Work Function Changecontrasting

confidence: 61%

Section: Electronic Structure Of Adsorbates (I) Work Function Changementioning

confidence: 99%

Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

Weiß

Ranke

2002

Progress in Surface Science

584

610

View full text Add to dashboard Cite

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“…Solvated electrons can be generated simply by adding an alkali metal to anhydrous liquid ammonia; the solvated electrons have lifetimes on the order of months for solutions which are free from oxygen and moisture. It can be expected that photoelectron (PE) spectroscopy of these liquid solutions may reveal insights as to the binding energies of different electron motifs in ammonia. , However, in a recent review of the spectroscopy of excess electrons in ammonia it is remarked that the electronic structure of neat liquid ammonia itself has not as yet been characterized through its photoelectron spectrum, although the PE spectrum of large ammonia clusters and ammonia ice on MoS 2 has been reported. The liquid PE spectrum would be a crucial complement to the known ammonia orbital energies in both vapor and amorphous ice; it is certainly a necessary prerequisite for an understanding of the band gap in liquid ammonia and to provide a more rounded understanding of excess electrons in liquid ammonia.…”

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confidence: 99%

Valence and Core-Level X-ray Photoelectron Spectroscopy of a Liquid Ammonia Microjet

et al. 2019

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Photoelectron spectroscopy of microjets expanded into vacuum allows access to orbital energies for solute or solvent molecules in the liquid phase. Microjets of water, acetonitrile and alcohols have previously been studied; however, it has been unclear whether jets of low temperature molecular solvents could be realized. Here we demonstrate a stable 20 μm jet of liquid ammonia (−60 °C) in a vacuum, which we use to record both valence and core-level band photoelectron spectra using soft X-ray synchrotron radiation. Significant shifts from isolated ammonia in the gas-phase are observed, as is the liquid-phase photoelectron angular anisotropy. Comparisons with spectra of ammonia in clusters and the solid phase, as well as spectra for water in various phases potentially reveal how hydrogen bonding is reflected in the condensed phase electronic structure.

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“…This reduction in threshold energy for ionization is a general phenomenon and has been ascribed to dielectric screening of the hole produced by UV irradiation in condensed matter. 62,63…”

Section: Ionization Energy In the Condensed Phase Lowered Because Of ...mentioning

confidence: 99%

CHAPTER 2. Extraterrestrial Photochemistry: Principles and Applications

Arumainayagam¹,

Herbst²,

Heays³

et al. 2021

Comprehensive Series in Photochemical &Amp; Photobiological Sciences

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Energetic processing of interstellar ice mantles and planetary atmospheres via photochemistry is a critical mechanism in the extraterrestrial synthesis of prebiotic molecules. Photochemistry is defined as chemical processes initiated by photon-induced electronic excitation, not involving ionization. In contrast, photons with energies above the ionization threshold initiate radiation chemistry (radiolysis). Vacuum-ultraviolet (6.2-12.4 eV) light may initiate photochemistry and radiation chemistry because the threshold for producing secondary electrons is lower in the condensed phase than in the gas phase. Approximately half of cosmic-ray induced photons incident on interstellar ices in star-forming regions initiate photochemistry while the rest initiate radiation chemistry. While experimental techniques such as velocity map imaging may be used to extract exquisite details about gas-phase photochemistry, such detailed information cannot be obtained for condensedphase photochemistry, which involves greater complexity, including the production of excitons, excimers, and exciplexes. Because a primary objective of chemistry is to provide molecular-level mechanistic explanations for macroscopic phenomena, our ultimate goal in this book chapter is to critically evaluate our current understanding of the photochemistry that likely leads to the synthesis of extraterrestrial prebiotic molecules.

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UPS measurements of molecular energy level of condensed gases

Cited by 80 publications

References 10 publications

Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

Surface chemistry and catalysis on well-defined epitaxial iron-oxide layers

Valence and Core-Level X-ray Photoelectron Spectroscopy of a Liquid Ammonia Microjet

CHAPTER 2. Extraterrestrial Photochemistry: Principles and Applications

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