The team, which included French and Spanish collaborators, used a variant of a technique called atomic force microscopy, or AFM.

BBC: Atomic bond types discernible in single-molecule images

Jonathan Wolf, of the Independent Film and Television Alliance, runs AFM.

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They are carried out at a scale so small that room temperature induces wigglings of the AFM's constituent molecules that would blur the images, so the apparatus is kept at a cool -268C.

BBC: Atomic bond types discernible in single-molecule images