Molecular interferometry a possible gravitational field measuring technique

Local static gravitational fields have little measurable influence on the propagation of light. However such fields do have a considerable influence on the propagation and phase of slow neutrons, but reactors have a low neutron brightness at low velocity. However, the molecular brightness of a bottle of gas at a few atmospheres pressure is about 1012 times greater than that of a reactor. The question then emerges, can optical elements be devised for neutral molecules? The author answers this question in the affirmative for neutral polar molecules, and comments that work has commenced in Melbourne to realise such devices. (Auth.)