  We solve the two-particle s-wave scattering for an ultracold atom gas
confined in a quasi-one-dimensional trapping potential which is periodically
modulated. The interaction between the atoms is included in terms of Fermi's
pseudopotential. For a modulated isotropic transverse harmonic confinement, the
atomic center of mass and relative degrees of freedom decouple and an exact
solution is possible. We use the Floquet approach to show that additional
photon-assisted resonant scattering channels open up due to the harmonic
modulation. Applying the Bethe-Peierls boundary condition, we obtain the
general scattering solution of the time-dependent Schr\"odinger equation which
is universal at low energies. The binding energies and the effective
one-dimensional scattering length can be controlled by the external driving.
