Resonances of the double-well potential of the state of H2

The B ″ B ¯ ← X 1 Σ g + photodissociation cross section of the H2 molecule has been measured and calculated recently by Glass-Maujean and collaborators [M. Glass-Maujean, S. Klumpp, L. Werner, A. Ehresmann, H. Schmoranzer, J. Phys. B: At. Mol. Opt. Phys. 40 (2007) F-19]. The excited state potential presents a double well. The cross section is oscillatory. The structure was explained as due to an extension in the continuum of the series of vibrational levels belonging to the inner or outer wells. It is shown that a dressed molecular picture is an efficient way to calculate this cross section which is derived from the decay rate of the initial state. Part of the structure is correlated with the resonances associated with the outer well of the excited electronic state.