A tailored laser pulse controls the formation of a molecular
bond between two atoms.
(June 10, 2015) The
result of a chemical reaction is dictated by energy potentials and
thermodynamics, but physicists have long hoped to steer reactions in new ways
with coherent light from lasers. For the first time, researchers demonstrate
the coherent control of the reaction by which two atoms form a molecule. The
achievement—coupled with other photocatalyst tools—could potentially lead to a
chemical assembly line, in which lasers slice and weld molecular pieces into a
desired end product.
Coherent control of chemical reactions, which was first
proposed thirty years ago, employs shaped laser pulses to place molecular
reagents in states that promote a rare reaction process. Several groups have
succeeded in controlling which bonds are cut in a target molecule (i.e.,
selective photodissociation). However, the coherent control of bond formation
has proven more elusive.