Amodel of quantized rotational motion of a diatomic molecule (like o2) is the quantum rotator: two particles of mass m are separated by a massless rod of fixed length 2r. this barbell is free to rotate in 3d about its center of mass, which is fixed in space at r-0. (a) express the classical ke of the rotator in terms of its angular momentum and the moment of inertia. since pe is constant for the rotator (and can be set equal to zero), substitute the quantum operators for the classical quantities to obtain the hamiltonian operator of the rotator in terms of the operator of angular momentum. (b) find the energy spectrum enı and the eigenfunctions ynim of the quantum rotator. (c) find the degeneracy of the energy levels of the rotator.