Vibrational spectra of methyllithium and its aggregates: A new interpretation from ab initio anharmonic calculations

N. Gohaud , Didier Bégué (1) , Claude Pouchan (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

The complete quartic force field of methyllithium (CH3Li) is computed at the B3LYP/cc-pVTZ level of theory. The vibrational energy levels calculated from a perturbational and a variational procedure are in agreement with the observed spectra except for the C-Li stretching and the symmetric methyl deformation modes for which a disagreement with the experimental assignment given by Andrews is apparent. This discrepancy between experiment and theory is so large that questions are raised either about a correct characterization of, or correct calculations for the monomeric species CH 3Li. Our theoretical study of methyllithium aggregates (CH 3Li)n, with n = 2, 3, 4 and 6, gives a new interpretation of the experimental data. © 2004 Elsevier B.V. All rights reserved.

Domaines: Chimie théorique et/ou physique

N. Gohaud, Didier Bégué, Claude Pouchan. Vibrational spectra of methyllithium and its aggregates: A new interpretation from ab initio anharmonic calculations. Chemical Physics, 2005, 310 (1-3), pp.85-96. ⟨10.1016/j.chemphys.2004.10.016⟩. ⟨hal-01598740⟩