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rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2005-6-22
pubmed:abstractText
Binary thin films of cobalt(II) phthalocyanine (CoPc) and cobalt(II) tetraphenylporphyrin (CoTPP) were prepared at submonolayer coverage on Au(111)/mica substrates byvapor deposition. All sample preparation and analysis were done under an ultrahigh vacuum. Scanning tunneling microscopy (STM) constant-current images of CoPc/CoTPP mixtures showed two close-packed surface structures, with different compositional percentages and some disorder. CoPc was also observed exclusively in one-dimensional chains and as single, isolated molecules below 220 K. Occupied and unoccupied orbital energy levels were identified by STM and tunnel-diode-based orbital-mediated tunneling spectroscopy. Occupied energy levels were also confirmed by ultraviolet photoelectron spectroscopy. The transient oxidation of the Co d(z2) orbital is identified in STM dI/dV(V) curves just negative of the 0 V sample bias for both molecules. Nearly identical constant-current contours are observed over the central Co2+ ions of CoTPP and CoPc, indicating that the attenuation of the d(z)2 orbital-mediated tunneling current induced by the structure of TPP relative to Pc is at most a factor of about 10. The orbital-mediated tunneling spectra of CoTPP and CoPc are distinctly different and allow these structurally similar species to be differentially identified.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
May
pubmed:issn
0743-7463
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4413-21
pubmed:year
2004
pubmed:articleTitle
Scanning tunneling microscopy study of the structure and orbital-mediated tunneling spectra of cobalt(II) phthalocyanine and cobalt(II) tetraphenylporphyrin on au(111): mixed composition films.
pubmed:affiliation
Department of Chemistry and Materials Science Program, Washington State University, Pullman, Washington 99164-4630, USA.
pubmed:publicationType
Journal Article