American Journal of Physics
If two bound nonrelativistic quantum particles are each subject to a nonlinear external potential, their Schrödinger equation does not separate in relative and center-of-mass coordinates. For this case, the details of internal state of the composite affect its center-of-mass properties. The extent of this internal state influence is examined for an exactly soluble one-dimensional model system.
Lock, James A., "Center-of-Mass Properties of Composite Systems Subject to Non-Linear External Interactions" (1983). Physics Faculty Publications. 15.
Lock, James A. "Center-of-Mass Properties of Composite Systems Subject to Non-Linear External Interactions." American Journal of Physics 51 (1983): 717-721.
Copyright 1983 American Association of Physics Teachers. The article appeared in American Journal of Physics 51 (1983): 717-721 and may be found at http://aapt.scitation.org/doi/abs/10.1119/1.13153