  A gamma-rigid solution of the Bohr Hamiltonian is derived for gamma=0
utilizing the Davidson potential in the beta variable. This solution is going
to be called X(3)-D. The energy eigenvalues and wave functions are obtained by
using an analytic method which has been developed by Nikiforov and Uvarov.
BE(2) transition rates are calculated. A variational procedure is applied to
energy ratios to determine whether or not the X(3) model is located at the
critical point between spherical and deformed nuclei.
