Observing chemical reactions in ultra slow motion

A chemical reaction, simply stated, is the conversion of reactants into products. Consider the following simple chemical reaction where nitrogen dioxide decomposes into nitric oxide and oxygen.

2NO₂ -> 2NO + O₂

This reaction, in reality, is believed to progress in two steps as shown below

2NO₂ -> NO₃  NO

NO₃ -> NO + O₂

However, only the products NO and O₂ can be detected. This is because, in the first intermediate step of the reaction, the production of NO₃ + NO is transient and takes place within, literally, no time. Instantaneously, NO₃ decomposes into NO₂ + O₂. Therefore, measure of transient intermediate steps of a chemical reaction is very difficult and in many cases, impossible. Knowledge of these intermediate steps of a chemical reaction is very useful. This will allow “quantum-state control” over the outcome of chemical reactions of interest to us.

Researchers have now come closer to achieving this quantum-state control by directly observing transient intermediates in a chemical reaction. They achieved this feat by cooling down the reaction to almost “absolute zero degree kelvin”. At this ultra-low temperatures, molecules have slow little energy that, in effect, their reactivity is slowed down. Therefore, an otherwise transient intermediate will become stable for a longer time in ultra-cold conditions. 

Researchers trapped potassium-rubidium gas molecules in a chamber at an extremely low temperature of only 500 x 10^-9 kelvin or 500 nanokelvin. In this chamber, gas molecules were constantly reacting with each other. researchers were able to detect the intermediate K₂Rb₂ molecules for the first time along with the reactants and products as per the following reaction.

2KRb -> K2Rb₂ -> K₂ + Rb₂

According to the author’s who performed these experiments and published it in Science, this research opens up many avenues. Specifically, in quantum mechanics which is a field of science that is used in engineering and machine designing.