Submicroscopic Scale

Smaller than can be seen with light. That is to say, photons are way to big and the objects way to small for the photons to bounce off and their dispersal pattern used to 'see' the object as is the case for microscopic and large objects.
Atoms and most molecules fall within this realm.

Very, very large molecules such as carbohydrates, lipids, polymers, proteins, DNA, carbon nanotubes, polyphenols, pharmaceutical frankenstein drugs, and such are macromolecules that can be seen under a microscope and NOT submicroscopic.

Particles smaller than atoms are subatomic