Difference between revisions of "Positional atomic precision"

Revision as of 16:57, 7 August 2017

"Atomically precise positioning" (APP) is a refinement to "atomic precision" (AP) in general.

When mentioning atomic precision (or atomically preciseness) in some cases it's important to distinguish between mere precision in bond topology and a stronger form: positional precision in space. In case of mere precision in bond topology atoms may still wiggle around much more than their own size, but which atoms are connected which other ones can still be precisely specified. It'ds about reproducibly created bond topology/connectivity (that stays well preserved).

In case of precision in position/space atoms must not wiggle around more than their own size. This is especially important in mechanosynthesis of gemstones. There the wiggling must be restrained enough to make placement errors sufficiently unlikely such that it becomes practically possible to build up larger functional structures. So a nano-manipulator with atomically precise positioning capability (APPC) can position work-pieces at sub Ångström distances.

Note: due to a confusion of "resolution" and "positional preciseness" by the wiki's author (sorry)
some pages linking here might still use the wrong interpretation of "resolution".
Repair work is in progress.

The term "atomically precise positioning" can be extended with terms like: manufacturing, technology, capability, ....
Corresponding short-hands respectively: APPM, APPT, APPC, ...

Relation to material stiffness

Atomically precise positioning capability is enabled by high stiffness materials and high stiffness materials allow mechanosynthesis with atomically precise positioning capability. So those two go hand in hand.

Atomically precise positioning:

• is akin to printing resolution (TODO: Why called resolution and not precision?)
• must not be confused with atomically precise topology
• makes direct mechanosynthetic fabrication of AP structures like one H atom or moiety at a time possible
• makes design and reasoning easier
• makes the creation of structures with higher performance and similar or higher efficiency (diffusion transport has free energy cost) than biological systems display possible (superlubricating interfaces).

Effect of (random) thermal drift and bending on positioning

Thermal expansion or bending through external forces can spoil correct positioning atomic resolution in 3D space over greater distances. Depending whether this is considered a (slow moving) random variable or a systematic offset error this might be considered an error in precision or accuracy respectively.

Thermal drift is a well known phenomenon by people working with scanning probe microscopes. Thermal drift isn't a problem in gem-gum factories though where relative distances between (sturdy) AP workpieces and (sturdy) AP tooltips are microscopic. Equally rough handling of a gem-gum factory (slight bending) when in operation may proof not to be too serious.

Related

• Atomic precision
• Stiffness
• Precision ... a general definition