Theoretical Analysis of the Electronic Structure and Molecular Properties of the Alkali Halides. I. Lithium Chloride

Results of a theoretical investigation of the electronic structure of LiCl within the SCF—LCAO—MO framework are discussed, giving special emphasis to the evaluation of various molecular properties. Computed values (followed by experimental values in parentheses) for the total energy E, equilibrium separation R_e, spectroscopic constants ω_e, ω_ex_e, and B_e, and the dipole moment μ, are E=−467.05466 a.u., R_e=3.825 a.u. (3.819 a.u.), ω_e=671.5 cm⁻¹ (641 cm⁻¹), ω_ex_e=4.67 cm⁻¹ (4.2 cm⁻¹), B_e=0.704 cm⁻¹ (0.706 cm⁻¹), ${\mu }_v\text{=7.2182+0.0753 (v+}\frac{1}{2}\text{)+0.0002 (v+}\frac{1}{2}{)}^2$ , and ${\mu }_v(\mathrm{exptl}\text{)=7.0853+0.0864 (v+}\frac{1}{2}\text{)+0.0006 (v+}\frac{1}{2}{)}^2$ . Computed dissociation energies, coupled with relativistic and correlation energy contributions estimated from atomic data, result in a value for D_e of 0.174 a.u. as compared with the experimental value of 0.178 a.u. Computed values for the field gradients at the nuclei have been combined with experimental values of the quadrupole coupling constants to yield, for the nuclear quadrupole moments of lithium and chlorine, Q_Li=−0.050×10⁻²⁴cm², Q³⁷_Cl=−0.084×10⁻²⁴cm², Q³⁵_Cl=−0.106×10⁻²⁴cm².