Transition from Molecular Complex to Quantum Solvation in 4HeNOCS

Francesco Paesani (1) , Alexandra Viel (1) , Franco Gianturco (2) , K. Birgitta Whaley (1)

1 Kenneth S. Pitzer Center for Theoretical Chemistry
2 Physics Department,Rome University "LaSapienza" - Physics Department,Rome University "LaSapienza"

We present fully quantum calculations of the rotational energy levels and spectroscopic rotational constants of the linear OCS molecule in variable size clusters of 4He. The rotational constants of OCS are found to decrease monotonically from the gas phase value as the number of helium atoms increases to N=6, after which the average constant increases to saturation at the large droplet value by N=20. The minimum is shown to indicate a transition from a molecular complex to a quantum solvated molecule, with the former characterized by floppy but near rigid behavior, while the latter is characterized by nonzero permutation exchanges and a smaller extent of rigid coupling.

Mots clés: Quantum Monte Carlo; Quantum dynamics; Helium clusters

Domaines: Chimie théorique et/ou physique; Physique Quantique [quant-ph]

Francesco Paesani, Alexandra Viel, Franco Gianturco, K. Birgitta Whaley. Transition from Molecular Complex to Quantum Solvation in 4HeNOCS. Physical Review Letters, 2003, 90 (7), pp.073401. ⟨10.1103/PhysRevLett.90.073401⟩. ⟨hal-01118305⟩