The track is a gold sample consisting of a perfect single crystal. But you have to clean the race track to be sure that there are only the nanocars and no other molecules from previous measurements.
Nanocar Race Part 4: Driving the Nanocar – Manipulation of single molecules
How can you move a single molecule? We could use our tip like a finger and push the nanocar. Actually this would also be possible at the nanoscale! In this case the tip needs to touch the molecule. But pushing the nanocar in this way is forbidden at the Nanocar Race. Only electric power is allowed! As we have shown before there is a tunneling current between tip and sample. We can use this current to inject electric power into the nanocar.
The molecule has different energy levels. Without any influence the molecule is in the ground state. If you change the voltage between the tip and the molecule, you can inject electrons in the excited state of the molecule. So it has a higher energy. By filling more and more electrons in the molecule which is done by ramping the bias voltage we also excite states where the molecule does vibrations or rotations. And then it moves.
We can control the direction of the movement by the position where we place the tip. The molecule always follows our tip when we inject electrons. So we know exactly where the molecule goes.
But then we have to scan again to see the molecule. Because we know where the molecule went after excitation, we can choose a small scan range around this area to get a quick image. The time for a scan is quite long in comparison to the electron injection. By choosing a small scan range at the right position we reduce the time we need to finish the race track at the Nanocar Race.
Nanocar Race 2017
The NanoCar Race is an event in which molecular machines compete on a nano-sized racetrack. These “NanoCars” or molecule-cars can have real wheels, an actual chassis…and are propelled by the energy of electric pulses! Nothing is visible to the naked eye, however a unique microscope located in Toulouse will make it possible to follow the race. A genuine scientific prowess and international human adventure, the race is a one-off event, and will be broadcast live on the web, as well as at the Quai des Savoirs, science center in Toulouse.
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