What does a molecule look like?

Have you ever seen a picture of a molecule or atom? Not a model like this ball-and-stick model of (R)-5-(1-chloroethyl)-2′,5′-dinitrobiphenyl-3-ol.


Have you ever seen an image of an actual atom or molecule?

Images of atoms and molecules exist. Here’s one:

Cesium and Iodine

The above image shows cesium and iodine atoms. It’s not a model, not something that someone created from imagination and information. It’s a rendering of a real physical object.

It’s not a photograph. It was rendered using a completely different process from photography. Photographs use light, and this molecule is not only much too small to see with the naked eye, it’s also smaller than the wavelength of visible light needed to see (or photograph) it with. Cesium is a big atom (or at least it’s big for an atom, anyway), and measures about 6/10 of a nanometer in diameter. The wavelengths of the optical spectrum range approximately from 400 nm to 700 nm.

How do you render an image, without light or photography, of an object that exists in a submicroscopic world below the world of the visual?

The image of cesium and iodine atoms was rendered with the Scanning Tunneling Microscope (STM), a non-optical device that uses electricity and quantum mechanics. From Wikipedia:

The STM is a non-optical microscope which employs principles of quantum mechanics. An atomically sharp probe (the tip) is moved over the surface of the material under study, and a voltage is applied between probe and the surface. Depending on the voltage electrons will “tunnel” (this is a quantum-mechanical effect) or jump from the tip to the surface (or vice-versa depending on the polarity), resulting in a weak electric current. The size of this current is exponentially dependent on the distance between probe and the surface.

Color (a function of light) is added after images are rendered by the STM. The data gathered by the STM are manipulated with custom graphics software to make the gathered information about a sub-visual object into something that the observer can process visually. Color and light effects are added to delinate different objects within the image, and to show curvature and other surface properties.

Here’s an image of some nickel atoms:

And some platinum atoms:

All of the STM images in this post are taken from the STM Image Gallery.

The STM was developed by Gerd Binnig and Heinrich Rohrer at the IBM Zurich Research Laboratory in the early 1980s. In 1986, their invention won them the Nobel Prize for Physics.

Learn more about the Scanning Tunneling Microscope here.

Here’s an image of individual tungsten atoms in a tungsten needle. The tungsten image was rendered with a Field Ion Microscope (FIM).

2 responses to “What does a molecule look like?

  1. This really helped!!! thanks

  2. This Really Helped ! Thanks !

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