Ultracold Chemical Reactions

The Team: Yu Liu, Andrei Gheorghe, Dr. Yen-Wei Lin, Dr. Ming-Guang Hu,

Chemical reactions can be surprisingly efficient at cold (1 mK) and ultracold temperatures (1 µK) due to the wave nature of atoms and molecules.  At these temperatures, non-classical effects such as wavefunction delocalization and tunneling through barriers, can dominate the reaction rate. A mere change of the quantum statistics of reagents at an energy typically near 10-8 kcal/mol, can further alter the reaction rate by a factor of 10 to 100.

Studies of reaction kinetics explore elementary reaction steps.  For example, textbook reactions of the sort AB + CD -> AC + BD that involved only covalent bonds were established to occur only with additional intermediate steps. Woodward- Hoffmann rules give an intuitive explanation based on molecular orbital pictures. However, such rules and intuitions may have to be set aside for reactions in the quantum regime, where reactants move slowly and interact for much longer durations. We are embarking to study unique 4-center reaction of 2 KRb -> K2+Rb2 at ultracold temperature.