Enhancement of metallic silver monomer evaporation by the adhesion of polar molecules to silver nanocluster ions

Journal Article · Thu May 11 04:00:00 UTC 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100019a061· OSTI ID:50789

Fagerquist, C K; Sensharma, D K; El-Sayed, M A ^[1]; Rubio, A; Cohen, M L ^[2]

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1. Univ. of California, Los Angeles, CA (United States)
2. Univ. of California, Berkeley, CA (United States)

We have compared the metallic evaporation channels from metastable [Ag{sub X=5,7,11}(AgI){sub Y=1-4}]{sup +} clusters in the first field free region of a double focusing mass spectrometer with that of the corresponding pure metallic clusters, [Ag{sub X=5,7,11}]{sup +}. It is found that the presence of the polar AgI molecules increases the rate of silver monomer evaporation relative to that of silver dimer evaporation. Using thermodynamic expressions for the heat of evaporation of the different evaporation processes and assuming the absence of reverse activation energies, an expression for the difference between the activation energy of silver monomer and dimer evaporation is derived. It is shown that dipole/induced-dipole forces resulting from the presence of AgI polar molecules lead to an enhancement of silver monomer evaporation if the polarizability of the pure metallic cluster ions increases with the number of Jellium electrons. Our theoretical calculations of the static polarizabilities of [Ag{sub x}]{sup +}, using time dependent density functional theory within the local density approximation, shows a smooth increase in the polarizabilities with the number of the Jellium electrons in these clusters. Finally, we observe that the enhancement of Ag monomer evaporation per AgI needed is smaller for clusters with an even number of AgI molecules than with an odd number of them. 46 refs., 5 figs., 2 tabs.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 50789
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 19 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
66 PHYSICS
ADHESION
DIPOLES
DISSOCIATION
ELECTRONIC STRUCTURE
EVAPORATION
ION PAIRS
MASS SPECTRA
MOLECULES
MONOMERS
SILVER
SILVER IODIDES
SILVER IONS