Direct observation of native DNA structures with the scanning tunneling microscope

Simulating Scanning Tunneling Microscope

Theory of the scanning tunneling microscope.

We present a theory for tunneling between a real surface and a model probe tip, applicable to the recently developed "scanning tunneling microscope." The tunneling current is found to be proportional to the local density of states of the surface, at the position of the tip. The effective lateral resolution is related to the tip radius R and the vacuum gap distance d approximately as [(2 A)(R +d...

Direct observation of C2 hydrocarbon-oxygen complexes on Ag(110) with a variable-low-temperature scanning tunneling microscope.

A variable-low-temperature scanning tunneling microscope (STM) was used to observe oxygen (O2), ethylene (C2H4), and acetylene (C2H2) molecules on a Ag(110) surface and the various complexes that were formed between these two hydrocarbons and oxygen at 13 K. Ethylene molecule(s) were moved to the vicinity of O2 either by STM tunneling electrons at 13 K or thermally at 45 K to form (C2H4)x-O2 (x...

Distinction of nuclear spin states with the scanning tunneling microscope.

We demonstrate rotational excitation spectroscopy with the scanning tunneling microscope for physisorbed H(2) and its isotopes HD and D(2). The observed excitation energies are very close to the gas phase values and show the expected scaling with the moment of inertia. Since these energies are characteristic for the molecular nuclear spin states we are able to identify the para and ortho specie...

Reproducible Fabrication of Scanning Tunneling Microscope Tips

Reproducible fabrication of Scanning Tunneling Microscope tips is carried out following an electrochemical procedure widely reported. Tips are made from 0.5 diameter tungsten wire. Controlling fabrication parameters (immersion in the electrochemical solution, current-voltage ranges, duration of the process, among others) we achieve aspect ratios of 0.68 and tip radii of 330 nm in the best case....