A FCI benchmark on beryllium dimer: The lowest singlet and triplet states

Wissam Helal (1) , Stefano Evangelisti (1) , Thierry Leininger (1) , Antonio Monari (2)

1 GMO - Groupe THEO (LCPQ)
2 SRSMC - Structure et Réactivité des Systèmes Moléculaires Complexes

The electronic structure of the beryllium dimer Be2 was investigated at valence Full-Configuration-Interaction (FCI) level, using a large cc-pV6Z basis set, (7s6p5d4f3g2h1i). This gives a total of 280 contracted Gaussian functions for the dimer, corresponding to a valence FCI space of about 185×106 symmetry-adapted Slater determinants. The adiabatic potential energy curves of the singlet ground View the MathML source and the triplet lower excited View the MathML source states were calculated, and the principal spectroscopic constants for the two states were evaluated. Our results are found to be very close to recent experimental values published in the literature.

Wissam Helal, Stefano Evangelisti, Thierry Leininger, Antonio Monari. A FCI benchmark on beryllium dimer: The lowest singlet and triplet states. Chemical Physics Letters, 2013, 568, pp.49-54. ⟨10.1016/j.cplett.2013.03.012⟩. ⟨hal-00872678⟩