Researchers Develop Technique to Control Chemical Reaction on Micro Scales


Researchers from University of Bath discovered technique to manipulate and control individual molecules for a millionth of a billionth of a second.

The new technique developed by researchers from University of Bath is the most sensitive way of controlling a chemical reaction on some of the smallest scales at the single molecule level. The research is expected to facilitate new possibilities across the fields of nanoscience and nanophysics. The Scanning Tunnelling Microscope (STM) is often used to observe reactions of individual molecules when excited by adding a single electron. In conventional method, a test-tube and a Bunsen burner is used to drive a reaction. In STM experiments, electrical current from the microscope is used to drive the reaction. The current is so small and similar to series of individual electrons hitting the target molecule. However, the entire experiment is a passive process and its mechanism can only be observed once the electron is added to the molecule.

However, when the researchers reviewed the data from the experiment, some anomalous results were discovered in a standard experiment. A conventional reaction always goes faster, when the electric current is turned up. However, in case of this experiment the reaction was slower. The researchers realized that the anomalous results were a way to control single-molecule experiments to an unprecedented degree. The research was published in the journal Science on September 07, 2018.

The team discovered that the duration required for the electron to stick to the target molecule can be reduced by over two orders of magnitude, by keeping the tip of the microscope within 600-800 trillionths of a meter close to the molecule being studied. According to the researchers, the tip and molecule interact to create a new quantum state that facilitates a new channel for the electron to hop to and from the molecule. This reduces the time spent by electron on the molecule, which in turn reduces the chances of that electron causing a reaction.