Excited states of the hydrogen molecule in magnetic fields: The triplet Sigma states of the parallel configuration - art. no. 023410

The hydrogen molecule in the presence of a homogeneous magnetic field is in vestigated for the parallel configuration in the complete regime of field s trengths B = 0 - 100 a.u. Up to seven excitations are studied for gerade as well as ungerade spin triplet states of Sigma symmetry with a high accurac y. The evolution of the potential-energy curves for the individual states w ith increasing field strength as well as the overall behavior of the spectr um are discussed in detail. A typical feature of many potential-energy curv es is the strong increase of the dissociation energy and decrease of the co rresponding equilibrium internuclear distance in the high-field regime. Str ong qualitative changes of the potential energies are found particularly wi thin the regime 0.01 less than or equal toB less than or equal to5 a.u., wh ere we observe among other things the field-dependent evolution of patterns of avoided crossings.