Models of the interaction of metal tips with insulating surfaces

• Thomas Trevethan,
• Matthew Watkins and
• Alexander L. Shluger

Beilstein J. Nanotechnol. 2012, 3, 329–335, doi:10.3762/bjnano.3.37

• −1/2 α|E|, where α is the atomic polarizability of the tip apex atoms and E is the electric field generated by the interaction, which is reproduced implicitly in the DFT calculations. Each of the tip models employed in these calculations (cluster tip, periodic tip) give similar qualitative results

• observed force difference. The polarizability could be affected by the quality of the basis set, k-point sampling and the pseudopotential used (the plane-wave code uses a pseudopotential constructed with Cr in a d5s1 state, whilst the present calculations include s2p6d5s1). At present, the full convergence

Transmission eigenvalue distributions in highly conductive molecular junctions

• Justin P. Bergfield,
• Joshua D. Barr and
• Charles A. Stafford

Beilstein J. Nanotechnol. 2012, 3, 40–51, doi:10.3762/bjnano.3.5

• characterizes the interaction of two quadrupoles and is a dielectric constant included to account for the polarizability of the core and σ electrons. Here i, j, k, and l are the Cartesian indices of the foregoing tensors and vectors. Altogether, this provides an expression for the interaction energy that is

Distinction of nucleobases – a tip-enhanced Raman approach

• Regina Treffer,
• Xiumei Lin,
• Elena Bailo,
• Tanja Deckert-Gaudig and
• Volker Deckert

Beilstein J. Nanotechnol. 2011, 2, 628–637, doi:10.3762/bjnano.2.66

• usually intense ring breathing mode of uracil at 800 cm−1 is not visible in the spectra. As those vibrations that involve polarizability changes parallel to the TERS tip axis are expected to be more enhanced than perpendicular vibrations, the lack of the ring breathing mode may be due to a flat