Knowledge Bank

Ab initio single determinant molecular orbital calculations using an extended basis set due to Dunning have been carried out on the donor-acceptor complexes $LiOH2,Li(OH2)2$ and $LiNH3$. Structures and energies of dissociation will be reported. Electron spin densities at the Li and N nuclei have been calculated. Their agreement with experimentally derived values of Meier et $al.1$ is quite good. Harmonic vibrational frequencies for the three complexes have been computed. The spectra consist of low-frequency modes involving lithium, and high-frequency perturbed molecular modes. The former have not yet been observed. For the latter, a shift of $17cm-1$ has been $reported2$ in the $H2O$ bending mode, a change of which the present calculations cannot reproduce. Finally, an attempt has been made, based on the present calculations, to interpret the matrix effects observed by Meier et al.