Intense laser light modifies the pairing of electrons

The quantum-mechanical exchange interaction between electrons, a consequence of the Pauli exclusion principle, can be specifically modified with intense infrared light fields on time scales of a few femtoseconds, as time-resolved experiments on sulfur hexafluoride molecules show. In the future, This finding could lead to bottom-up control of chemical reactions with lasers based purely on electrons, the “glue” of chemistry.