COMPUTATION OF THE WIDTHS OF DOUBLY EXCITED-STATES COUPLED BY EXTERNAL AC OR DC FIELDS

We have computed the variation of the widths of two doubly excited states of H-, the discrete 2p2 3P and the autoionizing 2s2p 3P-degrees, as a function of the intensity and of the on- and off-resonance frequency of a laser, and of the field strength of a DC field. In the field-free case, the width of the 2s2p 3P-degrees state is due to the Coulomb interaction with the H 1s-epsilon-p 3P-degrees channel and is found to be 6.5 meV,in agreement with previous theoretical and experimental investigations. When the fields are turned on, the calculation involves the simultaneous coupling of the two states and 15 open channels and was carried out according to a recently published many-electron many-photon theory.