Topological atomic precision
With atomic precision one refers to structures where the positions of all the included atoms are known in a topological sense meaning one knows which atom connects with which.
An atomically precise structure may well be floppy such that thermal movement makes the actual positions of the atoms completely unknown. Many base structures for self assembly (in technology level 0 and technology level I) are examples for floppy AP structures e.g. short DNA half strands (oglionucleotides).
- In technology level I whole sturdy structures out of sturdy AP-building blocks are assembled in a digital fashion. One is dealing with atomically precise structures but one only needs sub block size positioning precision for positional assembly.
- In technology level II and technology level III diamondoid materials are the main building material. They allow not only the topological position but also the position in three dimensional space to be known (positional atomic precision).
Atoms do roughly behave like a construction set with elastic linkages only if the right set of atoms is chosen. Metals with their undirected bonding tend to diffuse at room temperature destroying topological order and thus often do not preserve Atomic precision (AP) making them unsuitable for nanomachinery.