TY - JOUR
T1 - Dipole-dipole interactions among CH3Cl molecules on Ru(001)
T2 - Correlation between work function change and thermal desorption studies
AU - Livneh, T.
AU - Lilach, Y.
AU - Asscher, M.
PY - 1999/12/22
Y1 - 1999/12/22
N2 - Work function change measurements (ΔΦ) combined with temperature programmed desorption (TPD) were employed to study layer growth mechanism and the CH3Cl dipole-dipole interactions on Ru(001), over the temperature range of 97 K-230 K. The activation energy for desorption (Ea) and the molecular dipole moment (μ) both decrease from 55.9 kJ/mol and 2.44 D, at the zero coverage limit, to 38.6 kJ/mol and 1.27 D, at one monolayer. This coverage dependence originates from strong dipolar lateral repulsion among neighbor CH3Cl molecules. Using a model introduced by Maschhoff and Cowin (MC) [J. Chem. Phys. 101, 8138 (1994)], the isolated adsorbed molecule's dipole moment, μ0 (2.35 D) and polarizability α(8.1×10-24 cm3), were extracted from TPD data. These values agree very well with μ0 (2.12 D) and α(9.2×10-24 cm3) obtained from work function change measurements by employing the same MC model. The ability to simulate both TPD and work function change data over a wide coverage range within the framework of a single electrostatic model has been demonstrated. It enabled better understanding of fine details of surface dipolar interactions.
AB - Work function change measurements (ΔΦ) combined with temperature programmed desorption (TPD) were employed to study layer growth mechanism and the CH3Cl dipole-dipole interactions on Ru(001), over the temperature range of 97 K-230 K. The activation energy for desorption (Ea) and the molecular dipole moment (μ) both decrease from 55.9 kJ/mol and 2.44 D, at the zero coverage limit, to 38.6 kJ/mol and 1.27 D, at one monolayer. This coverage dependence originates from strong dipolar lateral repulsion among neighbor CH3Cl molecules. Using a model introduced by Maschhoff and Cowin (MC) [J. Chem. Phys. 101, 8138 (1994)], the isolated adsorbed molecule's dipole moment, μ0 (2.35 D) and polarizability α(8.1×10-24 cm3), were extracted from TPD data. These values agree very well with μ0 (2.12 D) and α(9.2×10-24 cm3) obtained from work function change measurements by employing the same MC model. The ability to simulate both TPD and work function change data over a wide coverage range within the framework of a single electrostatic model has been demonstrated. It enabled better understanding of fine details of surface dipolar interactions.
UR - http://www.scopus.com/inward/record.url?scp=0000492424&partnerID=8YFLogxK
U2 - 10.1063/1.480496
DO - 10.1063/1.480496
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AN - SCOPUS:0000492424
SN - 0021-9606
VL - 111
SP - 11138
EP - 11146
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 24
ER -