In more sophisticated experiments, two beams are allowed to intersect, producing scattering interactions or collisions between molecules in pairs, one from each beam.
The bridge beams are reinforced in places with steel beams.
The bridge beams were constructed with precast, prestressed concrete beams.
Most commonly, the molecules comprising the beam are at a low density; that is, they are far enough apart to move independently of each other.
Nowadays, full control over both the internal and external degrees of freedom of molecules in a beam is possible.
Subsequently, the chamber is filled with DNA molecules and a laser beam is incident on the gold substrate with a nanohole.
As a result, the tiny colour shift in a fraction of the beam is a fantastically precise measure of the molecules it has encountered.
A molecular beam is produced by allowing gas to enter a vacuum chamber through a small hole or slit in a box containing vapour of the molecules that are to make up the beam (see Figure).
