Abstract
The effects of an electronegative coadsorbate on the stimulated dissociation of a chemisorbed molecule are investigated using state-resolved laser-ionization spectroscopy of those dissociation fragments which leave the surface. Specifically, we examine the NO(2 =1/2,3/2) and O(3PJ) fragment energies and yields resulting from electron- (6 350 eV) stimulated dissociation of chemisorbed NO2 as a function of preadsorbed atomic O coverage. The most dramatic effect associated with O coverage (up to O=0.75 monolayer) is a large (a factor of 26) enhancement in the specific NO2 dissociation yield. There is also an O-induced narrowing of the translational energy distributions and a decrease in both the rotational and vibrational energy of the NO fragment. The dissociation threshold of 10 eV, together with lifetime arguments, suggest that the dominant excitation(s) are shallow-valence two-hole excitations. The above observations can be understood in terms of reduced substrate charge-transfer screening of these excitations. In addition, we observe a distinct propensity (>4:1 at low J) for populating the upper ( =3/2) over the lower ( =1/2) level of the spin-orbit-split NO(2 ) ground state, whereas the spin-orbit population of the O(3PJ) fragment is statistical (2J+1) within experimental error. The O(3PJ) yield derives from dissociation of nitro-bound NO2 (N end down); no O(3PJ) yield can be associated with side-bonded NO2.
| Original language | English |
|---|---|
| Pages (from-to) | 8679-8688 |
| Number of pages | 10 |
| Journal | Physical Review B |
| Volume | 45 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - 1992 |
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- Condensed Matter Physics
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Electronically stimulated adsorbate dissociation in the presence of an electronegative coadsorbate : (NO2+O) on Pt(111). / Orlando, T. M.; Burns, A. R.; Jennison, D. R.; Stechel, Ellen.
In: Physical Review B, Vol. 45, No. 15, 1992, p. 8679-8688.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Electronically stimulated adsorbate dissociation in the presence of an electronegative coadsorbate
T2 - (NO2+O) on Pt(111)
AU - Orlando, T. M.
AU - Burns, A. R.
AU - Jennison, D. R.
AU - Stechel, Ellen
PY - 1992
Y1 - 1992
N2 - The effects of an electronegative coadsorbate on the stimulated dissociation of a chemisorbed molecule are investigated using state-resolved laser-ionization spectroscopy of those dissociation fragments which leave the surface. Specifically, we examine the NO(2 =1/2,3/2) and O(3PJ) fragment energies and yields resulting from electron- (6 350 eV) stimulated dissociation of chemisorbed NO2 as a function of preadsorbed atomic O coverage. The most dramatic effect associated with O coverage (up to O=0.75 monolayer) is a large (a factor of 26) enhancement in the specific NO2 dissociation yield. There is also an O-induced narrowing of the translational energy distributions and a decrease in both the rotational and vibrational energy of the NO fragment. The dissociation threshold of 10 eV, together with lifetime arguments, suggest that the dominant excitation(s) are shallow-valence two-hole excitations. The above observations can be understood in terms of reduced substrate charge-transfer screening of these excitations. In addition, we observe a distinct propensity (>4:1 at low J) for populating the upper ( =3/2) over the lower ( =1/2) level of the spin-orbit-split NO(2 ) ground state, whereas the spin-orbit population of the O(3PJ) fragment is statistical (2J+1) within experimental error. The O(3PJ) yield derives from dissociation of nitro-bound NO2 (N end down); no O(3PJ) yield can be associated with side-bonded NO2.
AB - The effects of an electronegative coadsorbate on the stimulated dissociation of a chemisorbed molecule are investigated using state-resolved laser-ionization spectroscopy of those dissociation fragments which leave the surface. Specifically, we examine the NO(2 =1/2,3/2) and O(3PJ) fragment energies and yields resulting from electron- (6 350 eV) stimulated dissociation of chemisorbed NO2 as a function of preadsorbed atomic O coverage. The most dramatic effect associated with O coverage (up to O=0.75 monolayer) is a large (a factor of 26) enhancement in the specific NO2 dissociation yield. There is also an O-induced narrowing of the translational energy distributions and a decrease in both the rotational and vibrational energy of the NO fragment. The dissociation threshold of 10 eV, together with lifetime arguments, suggest that the dominant excitation(s) are shallow-valence two-hole excitations. The above observations can be understood in terms of reduced substrate charge-transfer screening of these excitations. In addition, we observe a distinct propensity (>4:1 at low J) for populating the upper ( =3/2) over the lower ( =1/2) level of the spin-orbit-split NO(2 ) ground state, whereas the spin-orbit population of the O(3PJ) fragment is statistical (2J+1) within experimental error. The O(3PJ) yield derives from dissociation of nitro-bound NO2 (N end down); no O(3PJ) yield can be associated with side-bonded NO2.
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U2 - 10.1103/PhysRevB.45.8679
DO - 10.1103/PhysRevB.45.8679
M3 - Article
VL - 45
SP - 8679
EP - 8688
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 15
ER -