A high-resolution electron energy loss spectroscopy study of the surface structure of benzene adsorbed on the rhodium(111) crystal face

Koel, Bruce E.; Crowell, J. E.; Mate, C. Mathew; Somorjai, Gábor A.

doi:10.1021/j150654a014

Cited by 138 publications

(106 citation statements)

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“…This assignment differs slightly from that of Lehwald et al [5] where the loss at ~1420 cm-1 was assigned to the v 9 of benzene. qur assignment, however, is consistent with more recent studies of benzene on other metal surfaces [9,10,11]. The difference in assignment does not charige the conclusion that benzene bonds to Pt(111) with its ring oriented parallel to the surface as indicated by the the intense out-' of-plane C-H bending mode (yCH) and the weak in-plane modes in the vibrational spectra.…”

Section: Co/c6h6/pt(111)supporting

confidence: 88%

“…When benzene and CO are coadsorbed, we observed depending on CO coverage two new and different ordered structures which can be labeled c(213x4)rect and (3x3). These LEED structures have been reported previously [9,12,15], but the authors did not realize at the time how important CO impurities from the background pressure (-5x1o-10 torr) were in ordering the structures.…”

Section: Co/c~6/rh(111)supporting

confidence: 66%

“…Benzene-d6 coverages were determined by comparing the Dz desorption yield to that of the (213x3)rect benzene-d6 structure. For the benzene coverages, we assume that there are two benzene molecules per (213x3)rect unit cell and that the D2 desorption yield is proportional to the benzene-d6 coverage since less than two percent of the benzene desorbs molecularly from Rh(111) (9]. CO and benzene coverages are defined as the ratio of adsorbed molecules to surface atoms.…”

Section: Co/c~6/rh(111)mentioning

confidence: 99%

“…Several previous studies of benzene on Pt(lll) and Rh(lll) surfaces [5,9] have tried to determine the adsorption site symmetry of benzene using HREELS. These studies concluded that the symmetry of adsorbed benzene was C3v(ad) since only a small number of benzene modes are observed in the HREEL spectra and those modes that are observed are consistent with a local symmetry of C3v(ad)• tt was thought that more modes would become dipole active if benzene was bonded to a site of lower symmetry and that these modes woula then be observed in the HREEL spectra.…”

Section: J •mentioning

confidence: 99%

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Carbon monoxide induced ordering of benzene on Pt(111) and Rh(111) crystal surfaces

Mate¹,

Somorjai²

1985

Surface Science

157

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Section: Co/c6h6/pt(111)supporting

confidence: 88%

Section: Co/c~6/rh(111)supporting

confidence: 66%

Section: Co/c~6/rh(111)mentioning

confidence: 99%

Section: J •mentioning

confidence: 99%

See 2 more Smart Citations

Carbon monoxide induced ordering of benzene on Pt(111) and Rh(111) crystal surfaces

Mate¹,

Somorjai²

1985

Surface Science

157

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“…Each chamber is equipped with LEED, Auger Electron Spectroscopy (AES), and a mass spectrometer for TDS. Two of the chambers, which have HREEL spectrometers, have been described previously [29,30]. The third chamber is designed for low temperature LEED studies.…”

mentioning

confidence: 99%

The surface structure and thermal decomposition of acetylene on the Rh(111) single crystal surface and the effect of coadsorbed carbon monoxide

et al. 1988

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The surface structure and thermal chemistry of acetylene. on the Rh(lll) crystal surface have been studied from 30 to BOO K using high resolution electron energy loss spectroscopy (HREELS), low energy electron diffraction (LEEO), and thermal desorption spectroscopy (TDS). Adsorbed acetylene on the Rh(lll) is disordered at 30 K, but orders into a (2 x 2) LEED structure at 60 K; this is the lowest ordering temperature that has been reported for chemisorbed acetylene on a metal surface. HREEL spectra of c 2 H 2 and c 2 D 2 ordered in the (2 x 2) structure at 77 K on Rh(lll) indicate that the 2 3carbon-carbon bond of chemisorbed acetylene rehybridizes between sp and sp At 270 K, chemisorbed molecular acetylene decomposes predominantly to CCH 2 species. Above 400 K, further decomposition to a mixture of CCH and CH species h observed. When CO and molecular acetylene are coadsorbed at 220 K, we observe a c(4 x 2) LEED structure rather than the (2 x 2) LEED structures observed for acetylene or CO adsorbed alone on Rh(lll). Also, chemisorbed acetylene, when coadsorbed with CO, decomposes at 270 K to a mixture of CCH 3 (ethylidyne) and CCH {acetylide) species rather than the CCH 2 species. 1. INTRODUCTION Studies of the bonding and reactivity of unsaturated hydrocarbon molecules adsorbed on transition metal single crystal surfaces are important for a molecular-level understanding of heterogeneous hydrocarbon catalysis. With the development over the last 20 years of ultra-high vacuum {UHV) technology and of surface sensitive spectroscopies, a data base of adsorption geometries and fragmentation pathways for prototype hydrocarbons adsorbed on well-defined -2 -single crystal metal surfaces is now accumulating.High resolution electron energy loss spectroscopy (HREELS) [1], in providing surface vibrational spectra, has been a particularly powerful technique for determining the identity of hydrocarbon adsorbates. In combination with other techniques like low energy electron diffraction (LEED) [2], it has also been possible to determine the adsorption geometry, the bond lengths and the bond angles for several hydrocarbon adsorbates.[3] These structural results have been well-complemented by the desorption products and kinetics measured in thenmal desorption spectroscopy (TDS) studies.These techniques have been extensively applied to study the adsorption of acetylene, the prototype alkyne. To date, HREELS has been used to study the bonding and reactivity of acetylene adsorbed on Ni(111) [4][5][6][7], Ni(100) [B,9], Ni(110) [10,11], Pd(111) [12,13], Pd(100) [14], Pd(110) [10], Pt(lll) [15,16], Cu(111) [10], Cu(110) [17], Ag(110) [1B], Fe(110) [19], Fe(111) [20], Ru(0001) [21], Re(0001) [22], Rh(111) [23], W(110) [24], W(111) [25], W(lOO) [26], and Si(lll) [27] surfaces. One of the major observations of these studies (except for the Ag(1l0) surface) was a large shift of the carbon-carbon stretchingfrequency from its value of 1974 em in gas phase acetylene to 1100-1400 em for chemisorbed molecular acetylene. Such a frequency sh...

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2018

Vibrational Spectra of Organometallics

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A high-resolution electron energy loss spectroscopy study of the surface structure of benzene adsorbed on the rhodium(111) crystal face

Cited by 138 publications

References 4 publications

Carbon monoxide induced ordering of benzene on Pt(111) and Rh(111) crystal surfaces

Carbon monoxide induced ordering of benzene on Pt(111) and Rh(111) crystal surfaces

The surface structure and thermal decomposition of acetylene on the Rh(111) single crystal surface and the effect of coadsorbed carbon monoxide

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