  A microscopic quantum ideal rotor-model Hamiltonian (distinct from that of
Bohr's rotational model) is derived for a rotation about a single axis by
applying a dynamic rotation operator to the deformed nuclear ground-state
wavefunction. It is shown that the microscopic ideal rotor Hamiltonian is
obtained only for a rigid-flow prescription for the rotation angle, with the
attendant rigid-flow kinematic moment of inertia. (For the center-of-mass
motion, the method predicts the correct mass.) Using Hartree-Fock variational
and second quantization methods, the ideal rotor-model Hamiltonian is reduced
to that of a self-consistent cranking model plus residual terms associated with
the square of the angular momentum operator and a two-body interaction. The
approximations and assumptions underlying the conventional cranking model are
revealed. The resulting nuclear Schrodinger equation, including a residual
two-body interaction and the residual part of the square of the angular
momentum, is then solved in the Tamm-Dancoff approximation using he eigenstates
of the self-consistent cranking model, with a self-consistent deformed harmonic
oscillator potential, as the particle-hole basis states. Good agreement is
obtained between the predicted and measured ground-state rotational-band
excitation energies, including the lowering of the excitation energy with
increasing angular momentum, in Ne-20 when the effects of a 3-D rotation are
simulated in the model.
