Excited Li and Na in He(n): influence of the dimer potential energy curves.

David Dell'Angelo (1) , Grégoire Guillon (1) , Alexandra Viel (1)

1 IPR - Institut de Physique de Rennes

The X(2)Σ ground and the A(2)Π and B(2)Σ first two excited states of Li-He and Na-He are determined using high level complete active space self-consistent field-multireference configuration interaction ab initio method. The obtained potentials differ from the ones proposed by Pascale [Phys. Rev. A 28, 632 (1983)], more strongly for the ground than for the excited states. Quantum diffusion Monte Carlo studies of small Li(∗)He(n) and Na(∗)He(n) with n ≤ 5 are performed using a diatomics-in-molecule approach to model the non-pair additive interaction potential. The sensitivity of our results to the A(2)Π and B(2)Σ potentials used is assessed by an analysis of the structure and of the energetics of the clusters. For these small clusters, the physical conclusions are essentially independent of the diatomic curves employed.

Mots clés: Excited states; Ab initio calculations; Molecular physics; Helium clusters; Spin orbit interactions; Quantum dynamics; Quantum Monte Carlo; Ground states; Potential energy surfaces

Domaines: Chimie-Physique [physics.chem-ph]; Chimie théorique et/ou physique; Physique [physics]

David Dell'Angelo, Grégoire Guillon, Alexandra Viel. Excited Li and Na in He(n): influence of the dimer potential energy curves.. Journal of Chemical Physics, 2012, 136 (11), pp.114308. ⟨10.1063/1.3693766⟩. ⟨hal-00909448⟩