Photodissociation dynamics of a hydrogen molecule via vibrationally excited superexcited states has been studied through the angular-momentum population of an excited hydrogen atom with the principal quantum number 3. The population shows a strong dependence on the incident photon wavelength in the longer wavelength region and a weak dependence in the shorter wavelength region. The population seems to converge to the equal partition as the incident photon wavelength becomes shorter. It is shown that the Rosen-Zener-type transition between the three states, not two states, at a large internuclear distance plays an important role in the dissociation dynamics. A close multilevel problem should be remarked even for a simple system such as a hydrogen molecule.