Adiabatic energies and radial couplings of the 3Σ+u states of H2

We present a calculation of the potential energy curves of the 3Σ+u states of the H2 molecule in the region R=1–30 a.u. The features of the correlation diagram are discussed, and a new series of avoided crossings in the region of R<5 a.u. is predicted. We calculate and analyze the radial couplings which are of interest in the study of the excitation process H(1s)+H(1s)→H(2s,2p)+H(1s). Finally, we introduce a simple analytical model which accounts for the 2 3Σ+u−3 3Σ+u interaction.