What are the shortcomings of the rigid rotator model?

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What are the shortcomings of the rigid rotator model? (A) Does not work for larger molecules, only for diatomics (B) Does not take into account flexible bonds (C) Both (A) and (B)

What are the shortcomings of the rigid rotator model? (A) Does not work for larger molecules, only for diatomics (B) Does not take into account flexible bonds (C) Both (A) and (B) The concept of the rigid rotator can be extended to any molecular size. For an arbitrary molecule, the moment of inertia is: where the sum runs over all atoms, the mj are the atomic masses and the rj are the distances of the atoms from the axis of rotation (NOT the center of mass!!!) rj