Abstract
Adsorption of CO on Cs-precovered Ru(001) with one-monolayer coverage (θCs = 0.33) has been investigated by means of electron energy loss spectroscopy (EELS), temperature-programmed desorption (TPD), low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). We found unusual adsorption of CO on the Cs(1 ML) Ru(001) surface. Gaseous CO adsorbs on the completely Cs-precovered surface at 85 K to a saturation coverage of 0.23. Although the low-resolution EELS and UPS results indicate that CO molecularly adsorbs on this surface, the CO stretching mode is not observed in the specular mode of high-resolution EELS but clearly appears at quite a low frequency of 1245 cm-1 in the off-specular mode. From a combination of the EELS, TPD and XPS experiments, we propose an adsorption model in which the CO molecules displace one-fourth of the Cs adatoms from the preadsorbed Cs monolayer, resulting in formation of a double-layer structure, Cs Cs + CO Ru(001); the displaced Cs atoms adsorb on the "rotated-p(2 × 2)" lattice which is composed of Cs and CO with a ratio of 1 : 1. In this adsorption state, it is considered that the CO species has an inclined or a side-on-bonded geometry and that the CO dipole is effectively screened by the second-layer Cs. This complete screening of the CO dipole is explained in terms of combined effects of the embedding of CO into the double-layer structure, a large polarizability of Cs and laterally delocalized electrons in the double-layer structure.
| Original language | English |
|---|---|
| Pages (from-to) | 39-54 |
| Number of pages | 16 |
| Journal | Surface Science |
| Volume | 334 |
| Issue number | 1-3 |
| DOIs | |
| Publication status | Published - 1995 Jul 10 |
| Externally published | Yes |
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Keywords
- Alkali metals
- Carbon monoxide
- Chemisorption
- Electron energy loss spectroscopy
- Low-energy electron diffraction (LEED)
- Ruthenium
- Surface relaxation and reconstruction Thermal desorption spectroscopy
- Vibrations of adsorbed molecules
- Visible and ultraviolet photoelectron spectroscopy
- X-ray photoelectron spectroscopy
ASJC Scopus subject areas
- Materials Chemistry
- Surfaces, Coatings and Films
- Condensed Matter Physics
- Surfaces and Interfaces
- Physical and Theoretical Chemistry
Cite this
Adsorption of CO on Cs-precovered Ru(001) : formation of a double-layer structure Cs Cs + CO Ru and complete screening of the CO dipole. / Kondoh, Hiroshi; Nozoye, H.
In: Surface Science, Vol. 334, No. 1-3, 10.07.1995, p. 39-54.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Adsorption of CO on Cs-precovered Ru(001)
T2 - formation of a double-layer structure Cs Cs + CO Ru and complete screening of the CO dipole
AU - Kondoh, Hiroshi
AU - Nozoye, H.
PY - 1995/7/10
Y1 - 1995/7/10
N2 - Adsorption of CO on Cs-precovered Ru(001) with one-monolayer coverage (θCs = 0.33) has been investigated by means of electron energy loss spectroscopy (EELS), temperature-programmed desorption (TPD), low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). We found unusual adsorption of CO on the Cs(1 ML) Ru(001) surface. Gaseous CO adsorbs on the completely Cs-precovered surface at 85 K to a saturation coverage of 0.23. Although the low-resolution EELS and UPS results indicate that CO molecularly adsorbs on this surface, the CO stretching mode is not observed in the specular mode of high-resolution EELS but clearly appears at quite a low frequency of 1245 cm-1 in the off-specular mode. From a combination of the EELS, TPD and XPS experiments, we propose an adsorption model in which the CO molecules displace one-fourth of the Cs adatoms from the preadsorbed Cs monolayer, resulting in formation of a double-layer structure, Cs Cs + CO Ru(001); the displaced Cs atoms adsorb on the "rotated-p(2 × 2)" lattice which is composed of Cs and CO with a ratio of 1 : 1. In this adsorption state, it is considered that the CO species has an inclined or a side-on-bonded geometry and that the CO dipole is effectively screened by the second-layer Cs. This complete screening of the CO dipole is explained in terms of combined effects of the embedding of CO into the double-layer structure, a large polarizability of Cs and laterally delocalized electrons in the double-layer structure.
AB - Adsorption of CO on Cs-precovered Ru(001) with one-monolayer coverage (θCs = 0.33) has been investigated by means of electron energy loss spectroscopy (EELS), temperature-programmed desorption (TPD), low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). We found unusual adsorption of CO on the Cs(1 ML) Ru(001) surface. Gaseous CO adsorbs on the completely Cs-precovered surface at 85 K to a saturation coverage of 0.23. Although the low-resolution EELS and UPS results indicate that CO molecularly adsorbs on this surface, the CO stretching mode is not observed in the specular mode of high-resolution EELS but clearly appears at quite a low frequency of 1245 cm-1 in the off-specular mode. From a combination of the EELS, TPD and XPS experiments, we propose an adsorption model in which the CO molecules displace one-fourth of the Cs adatoms from the preadsorbed Cs monolayer, resulting in formation of a double-layer structure, Cs Cs + CO Ru(001); the displaced Cs atoms adsorb on the "rotated-p(2 × 2)" lattice which is composed of Cs and CO with a ratio of 1 : 1. In this adsorption state, it is considered that the CO species has an inclined or a side-on-bonded geometry and that the CO dipole is effectively screened by the second-layer Cs. This complete screening of the CO dipole is explained in terms of combined effects of the embedding of CO into the double-layer structure, a large polarizability of Cs and laterally delocalized electrons in the double-layer structure.
KW - Alkali metals
KW - Carbon monoxide
KW - Chemisorption
KW - Electron energy loss spectroscopy
KW - Low-energy electron diffraction (LEED)
KW - Ruthenium
KW - Surface relaxation and reconstruction Thermal desorption spectroscopy
KW - Vibrations of adsorbed molecules
KW - Visible and ultraviolet photoelectron spectroscopy
KW - X-ray photoelectron spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=0029341506&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029341506&partnerID=8YFLogxK
U2 - 10.1016/0039-6028(95)00425-4
DO - 10.1016/0039-6028(95)00425-4
M3 - Article
AN - SCOPUS:0029341506
VL - 334
SP - 39
EP - 54
JO - Surface Science
JF - Surface Science
SN - 0039-6028
IS - 1-3
ER -