  We have computed exactly the energy spectrum and corresponding wave functions
of two bosonic particles, which are confined in a spherically symmetric
shell-shaped trap and interact with each other via a three-dimensional
zero-range potential. Confinement induced resonances (CIRs), originating
entirely from the strong coupling of the relative and center-of-mass motions of
the two particles, are identified as avoided crossings at certain values of the
shell radius. By working close to the found CIRs, these results offer a new way
to enhance the atom-atom interaction in the atomic gas by tuning only the
geometrical parameters of the shell.
