Photon- and electron-induced chemistry of chlorobenzene on Ag(111)

Article abstract of DOI:10.1063/1.458493

The surface chemistry, induced by UV photons and low energy electrons, of chlorobenzene (C6H5Cl) on Ag(111) has been studied.C6H5Cl adsorbs molecularly on Ag(111) at 100 K and desorbs molecularly at 170 K (physisorbed) and 230-240 K (chemisorbed) with no thermal decomposition.The adsorption is accompanied by a surface work function change (ΔΦ) of -0.65 eV at one monolayer and -0.9 eV at multilayer coverages.Both UV photons and low energy electrons induce the decomposition of adsorbed C6H5Cl.The energy threshold for the decomposition is 3.5-3.8 eV for photons and ca. 5 eV for electrons.For photons and < 12 eV electrons, the decomposition involves only C-Cl bond cleavage, producing surface phenyl groups and Cl atoms.Phenyl groups recombine and desorb as biphenyl at 390-400 K during post-irradiation temperature programmed desorption (TPD).They do not dehydrogenate.However, for electron energies higher than ca. 12 eV, the decomposition involves cleavage of C-H, C-Cl, and, probably, C-C bonds.In this case, post-irradiation TPD shows the desorptions of H2, HCl, AgCl, benzene, biphenyl, and C6H5Cl with C left on the surface.The cross section for photodissociation is 3 x 10²¹ cm² at 254 nm and decreases with increasing wavelength.The cross section for the electron-induced decomposition (EID) is 8 x 10¹⁷ cm² (upper limit) at 50 eV and decreases with electron energy.The photodissociation on the surface is ascribed to direct photon induced n -> ?^* transition and/or photoexcited electron attachment processes.Compared to the gas phase, the photodissociation threshold is red shifted.This is qualitatively explained by direct excitation process assuming an effective stabilization of the excited C6H5Cl by Ag(111) (strong adsorbate-substrate interactions) and/or "hot" electrons.EID by < 12 eV electrons probably involves dissociative electron attachment and electronic excitation processes; EID by > 12 eV electrons also involves ionization processes.

Full text of DOI:10.1063/1.458493

Photon and electroninduced chemistry of chlorobenzene on Ag(111)
X.L. Zhou and J. M. White
Citation: The Journal of Chemical Physics 92, 5612 (1990); doi: 10.1063/1.458493
View online: http://dx.doi.org/10.1063/1.458493
View Table of Contents: http://scitation.aip.org/content/aip/journal/jcp/92/9?ver=pdfcov
Published by the AIP Publishing
Articles you may be interested in
Time dependent changes in extreme ultraviolet reflectivity of Ru mirrors from electron-induced surface
chemistry
J. Appl. Phys. 111, 063518 (2012); 10.1063/1.3691604
Low energy electroninduced chemistry of biacetyl on Ag(111)
J. Vac. Sci. Technol. A 14, 1684 (1996); 10.1116/1.580319
Electroninduced surface chemistry: Production and characterization of NH2 and NH species on Pt(111)
J. Vac. Sci. Technol. A 14, 1516 (1996); 10.1116/1.580288
Electroninduced surface chemistry: Synthesis of NH x fragments on Ag(111)
J. Vac. Sci. Technol. A 14, 1453 (1996); 10.1116/1.579968
Photon versus electroninduced decomposition of Fe(CO)5 adsorbed on Ag(111): Iron film deposition
J. Vac. Sci. Technol. A 9, 1563 (1991); 10.1116/1.577662
This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
147.143.2.5 On: Sat, 20 Dec 2014 15:01:39

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1

This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to IP:
47.143.2.5 On: Sat, 20 Dec 2014 15:01:39
1