抄録
A special class of molecules, symmetric tops such as CH3Br, has dipole moments that are not averaged to zero as the molecules rotate. “Up” and “down” orientations of these molecules in a weak electric field have different energies and these orientations can be separated in an inhomogeneous electric field. Using such an inhomogeneous field, we have produced molecular beams oriented in space and have studied how this orientation affects chemical reactivity. Orientation is important. In the experiments discussed, an electron is transferred from a donor alkali atom to the LUMO of an oriented molecule. The stereochemistry of the transfer depends on the spatial extent of the LUMO, but the detection of the product (and the identity of the product) depends on the energy and the location of the donor.
