Looking at molecules

Figure 2 An AFM scans with a fine probe to build up an image

Less than a decade ago, the arrangements of atoms in molecules could not be seen directly, but physics-based techniques are now changing this.

In atomic force microscopy (AFM, Figure 1) a probe with a single-atom tip is scanned slowly across a surface, and the resulting tiny movements are detected by a laser beam and used to build up an image (Figure 2). AFM can be used to make images of individual molecules. Figure 3 shows a hexabenzocoronene (HBC) molecule, which is formed from six benzene rings (C6H6) and has a diameter of 1.4nm. The HBC, which is being studied as a potential nanomaterial, was made at Centre National de la Recherche Scientifique (CNRS) in Toulouse, France, and imaged using an AFM by IBM researchers.