Computational Details of Strontium Dimer
Potentials dissociating to the 1S+1P
and 1S+3P asymptotes
The multiconfiguration basis set for the calculation of the excited state
potentials dissociating to the 1S+1P and
1S+3P asymptotes of the Sr2 molecule is based
on the Dirac-Fock atomic orbitals belonging to the [1s2
2s2 2p6 3s2 3p6 3d10
4s2] 4p6 5s2 configuration. Additional
Dirac-Fock 5p and 4d orbital and Sturmian 6s and 6p orbitals are included. The
closed shells
1s22s23s23p63d104s2 +
1s22s23s23p63d104s2
form the core of the molecule and no excitations from these shells will be
allowed. The 4p6, 5s2, 5p, and 4d orbitals are valence
orbitals and single and double occupation and excitation from these orbitals
occur. The Sturmian 6s and 6p orbitals are virtual orbitals with double
occupation allowed. Covalent and ionic configurations are constructed by
distributing electrons from the valence orbitals in all allowed ways over the
orbitals. There are 393 nonrelativistic molecular configurations and 2290
relativistic configurations. The potential curves are calculated based on the
relativistic Hamiltonian in order to take into account the spin-orbit
splittings of the excited states. There are sixteen  g/u± relativistic potentials dissociating
to the 1S+1P and 1S+3P asymptotes.
Twelve of these potentials dissociate to the 1S+3P
asymptotes. Non relativistic labels valid at the short internuclear separations
are shown. The zero of energy is located at the dissociation limit of the
ground state of Sr2.
Potentials dissociating to the 3P+3P asymptotes
The multiconfiguration basis set for the calculation of the highly excited state
potentials dissociating to the 3P+3P asymptotes of the
Sr2 molecule is based on the Dirac-Fock atomic orbitals belonging to
the [1s2 2s2 2p6 3s2 3p6
3d10 4s2] 4p6 5s5p configuration. Additional
Dirac-Fock 4d orbital and Sturmian orbitals labeled 6s and 6p are included. The
closed shells
1s22s22p63s23p63d104s2 +
1s22s22p63s23p63d104s2
form the core of the molecule and no excitations from these shells will be
allowed. The 4p6, 5s2, 5p, and 4d orbitals are valence
orbitals and single and double occupation and excitation from these orbitals
occur. Covalent and ionic configurations are constructed by distributing
electrons from the valence orbitals in all allowed ways over the orbitals. This
leads to the same number of molecular configuration as in the calculation for
the lower lying excited states. Again the potential curves are calculated based
on the relativistic Hamiltonian in order to take into account the spin-orbit
splittings of the excited states.
The number of relativistic potentials g/u+/- = 0, 1, 2, 3, 4 dissociating
to the 3P+3P asymptotes is now significantly larger. The
zero of energy is again at the dissociation limit of the ground state of
Sr2. Some of the 0+ and 0- curves are
degenerate on the scale of the figures.
Nonrelativistic labels are indicated on the figures but can only be used to
label short range potentials.
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