Tracing electronic pathways in molecules by using inelastic tunneling spectroscopy.
Using inelastic electron tunneling spectroscopy (IETS) to measure the vibronic structure of nonequilibrium molecular transport, aided by a quantitative interpretation scheme based on Green's function-density functional theory methods, we are able to characterize the actual pathways that the electrons traverse when moving through a molecule in a molecular transport junction. We show that the IETS observations directly index electron tunneling pathways along the given normal coordinates of the molecule. One can then interpret the maxima in the IETS spectrum in terms of the specific paths that the electrons follow as they traverse the molecular junction. Therefore, IETS measurements not only prove (by the appearance of molecular vibrational frequencies in the spectrum) that the tunneling charges, in fact, pass through the molecule, but also can be used to determine the transport pathways and how they change with the geometry and placement of molecules in junctions.
Troisi
Alessandro
A
Department of Chemistry and Centre for Scientific Computing, University of Warwick, Coventry CV4 7AL, United Kingdom.
Beebe
Jeremy M
JM
Picraux
Laura B
LB
van Zee
Roger D
RD
Stewart
Duncan R
DR
Ratner
Mark A
MA
Kushmerick
James G
JG
D000478:Alkylation; D000873:Anthracenes / Q000737:chemistry; D003198:Computer Simulation; D004583:Electrons; D004986:Ether / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D013057:Spectrum Analysis / Q000379:methods*; D013438:Sulfhydryl Compounds / Q000737:chemistry
D000873:Anthracenes; D013438:Sulfhydryl Compounds; D004986:Ether; C034020:anthracene