Structural and Thermochemical ab Initio Studies of Lanthanide Trihalide Molecules with Pseudopotentials

Autor: Laurent Joubert, Gérard Picard, Jean-Jacques Legendre
Rok vydání: 1998
Předmět:
Zdroj: Inorganic Chemistry. 37:1984-1991
ISSN: 1520-510X
0020-1669
DOI: 10.1021/ic970350v
Popis: Structural and vibrational frequency studies have been carried out for 30 lanthanide trihalide molecules LnX3 (Ln = La−Lu; X = Cl, F) using ab initio quasi-relativistic effective core potentials at Hartree−Fock and Moller−Plesset post-Hartree−Fock levels of theory. A planar D3h geometry was obtained for all trichloride molecules. In accordance with previous theoretical works, a C3v structure was clearly established for the majority of the trifluorides. Calculated bond lengths and vibrational frequencies are in good agreement with the experimental data. Therefore, thermochemical functions have been estimated from thermostatistics calculations combined with our quantum mechanics results. The electronic partition function is crucial in order to be in accordance with experimental data tables, especially for temperatures higher than 500 K. A simple example of thermochemical equilibrium clearly proves the validity of the estimated functions in the case of the lanthanum halides.
Databáze: OpenAIRE