Can the De Broglie wavelength of a composite system (like a molecule) be derived as opposed to being calculated from the composite mass?
EDIT: @Dr jh, interesting relation you have derived. However, that is a rewrite of the original DeBroglie equation albeit using the λ variables. De Broglie guessed his solution by setting relativity constraints and came up with the frequency of the particle in its rest frame as f=m0c2h. I guess we can reformulate my question as to why does a particle acquire such a frequency as it seems to be a property of the bound system so we can for a moment ignore it is composite. What underlying physics gives the particle this frequency. Put another way, if we had a large ball over water and we see it bobbing up and down, we would assume something is pushing it, something like a water wave. Can we do something similar here and assume that the bound system acquired it's proper time frequency somehow by resonating to an underlying wave in the vacuum? What's interesting in the way De Broglie derived his solution, and I have seen this only in rare QM books, is that the particle has an associated spatially flat (constant phase) wave which then when observed from the point of a moving frame looks like a plane wave along the direction of motion with the known λ. No other wave shape in the particle's frame except the constant phase wave would produce such a relationship.