Molecules atoms moieties and molecular machine elements like DMEs are said to be in the machine phase when they are fixated to a place or fixated to controlled axes (controlled degrees of freedom) such that thermal movement can't move them to unknown places or bring them in an unknown states.
- Nanosystems 1.2.2.a A machine-phase system is one in which all atoms follow controlled trajectories (within a range determined in part by thermal excitation).
Since assembly at the nanocosm is done blindly it is important to know where you left your things. Thus one wants to work in the machine phase. Searching and grabbing your tools like we do in the makro world does not work. Once one let go of a smaller molecule its as good as impossible to catch it again by grabbing it sterically (meaning with shape not chemical reactivity) one can imagine this as the molecule being supersleazy and superfast. As a sidenote: Light isn't usable at the nanocosm it has either too long wavelength or it's too energetic and needs too big generation and sensing facilities that are beyond simple nanomechanics.
Synonymous to "machine phase" the term "eutactic envirounment" (eutactic ~ well ordered) can be used. (not to confuse with eutectic)
Machine phase chemistry
Performing chemistry in machine phase it is called machine phase chemistry or mechanosynthesis. It greatly accelerates reactions rates (compensating lower densities of reaction sites) and one obviously can freely choose where one wants each reaction to occur.
- Nanosystems 1.2.2.a Machine-phase chemistry describes the chemical behavior of machine-phase systems, in which all potentially reactive moieties follow controlled trajectories.
Partial machine phase in biological and diamondoid systems
When a DMME bearing is fixed on an axle but freely allowed to rotate one can think of this as the bearing being only partly in the machine phase. Though not in a strong sense biological systems sometimes operate in machine phase too. Enzymes binding two reactants at the same time and acting like a vibrating hinge (like chattering teeth) that repeatedly bring the reactants together can dramatically increase reaction rates. This is often described as an increase of effective concentration (waybackmachine) (direct link dead).