THE EIGENSPECTRUM OF THE RELATIVISTIC 2-CENTER HAMILTONIAN IN THE DIATOMIC BASIS OF BOUND HYDROGENLIKE DIRAC-SPINORS

During heavy ion collisions below the Coulomb barrier adiabatic molecu lar orbitals are formed for the inner electrons. For systems with tota l changes exceending Z = Z(1) + Z(2) similar or equal to 60 relativist ic effects are important and we, therefore, use the two-center Dirac H amiltonian to describe the dynamics. We investigate the method to appr oximate these molecular orbitals by an expansion in a di-atomic basis of Dirac wave functions and determine the binding energies by a variat ion of the expansion coefficients. Deviations from adiabaticity are ta ken into account to first order in the relative velocity (v/c similar to 0.1) of the nuclei which is considerably smaller than the electron velocity.