TRANSITIONS BETWEEN SHIFTED LANDAU STATES AND PHOTOIONIZATION OF THE HYDROGEN-ATOM MOVING IN A STRONG MAGNETIC-FIELD

Motion of a neutral two-body system transverse to a uniform magnetic field breaks the axial symmetry and causes a shift Of the wavefunction outward from the Coulomb well. Therefore the preferable position of the centre of the transverse basis for the wavefunction expansion depends on the motion. In strong magnetic fields, the most appropriate is a set of Landau functions which describe the states of free charged particles. We employed this basis shifted with respect to the Coulomb well and considered radiative transitions between eigenstates with different shifts. Transverse parts of the dipole matrix elements are calculated analytically. The expressions obtained enable one to apply the adiabatic approximation to the photoionization of a moving hydrogen atom with the choice of the transverse (Landau) parts of wavefunctions being localized in the Coulomb and magnetic wells for the initial (ground) and final (continuum) states, respectively. Contrary to the usual adiabatic approach, this method gives good agreement with more precise non-adiabatic calculations.