A theoretical study on the LaF₃ molecule embedded in argon matrix

Abstract

ABSTRACT:The LaF 3 ⅐Ar n (n ϭ 1-21) clusters have been proposed as models to account for the matrix effects on the molecular properties of the LaF 3 molecule isolated in argon solid matrix at cryogenic temperature. Because of the strong Lewis acid character of the LaF 3 molecule, there is a substantial electron-density transfer from the argon atoms to the molecule that induces important geometrical changes in the structure and vibrational frequencies. The present bottom-up approach reveals the formation of two sets of structures close in energy having the D 3h -LaF 3 and the C 3v -LaF 3 . The D 3h -LaF 3 structures are more compact with respect to the C 3v series. The largest investigated cluster of the D 3h series, the LaF 3 ⅐Ar 21 resembles an hcp structure with the LaF 3 occupying the central substitutional site that it is expected to be energetically preferred. The C 3v -LaF 3 structures are more stable for lighter clusters and their high formation rates in the gas-phase, immediately before matrix incorporation, could explain experimental IR/Raman results that point to a pyramidal shape for the molecule in argon matrix.

Relativistic Pseudopotentials: Their Development and Scope of Applications

“…Tsukamoto and co-workers found that dynamic electron correlation is indispensable for obtaining reliable bond distances, whereas static electron correlation has only little influence . For DyX 3 (X = Cl, Br, I), it has been found that 4f subshell does not influence the geometry of the monomers, but obviously affects their dimers (DyX 3 ) 2 (X = Cl, Br, I). ,, According to the calculations, DyX 3 (X = Br, I) probably forms both planar and pyramidal DyX 3 units in an inert matrix, leading to the appearance of two symmetric stretching frequencies observed by the experimentalists. , Similarly, nearby C 3 v and D 3 h structures were found for LaF 3 in Ar n clusters ( n = 1–21) at the MP2 level by Lanza using the shape-consistent La PP of Stevens et al…”

Curious matrix effects: a computational, electron diffraction, and vibrational spectroscopic study of dysprosium triiodide

“…These species can polarize the electron distribution of the closed-shell noble gases. Examples include molecules involving main group elements and transition metals, 7,8,9,10 lanthanides, 11 and actinides 12, 13 as well. A review on related structures also communicates several cases in which the shape of molecules embedded in matrices is influenced by such interactions.…”