Spin-orbit configuration interaction study of the electronic spectrum of antimony iodide Original Research Article

Relativistic effective core potentials (RECPs) have been employed in the framework of a spin-orbit configuration interaction (CI) approach to compute potential energy curves for the lowest-lying electronic states of the SbI molecule, as well as the Einstein coefficients of spontaneous emission for transitions between them. In contrast to systems such as arsenic and antimony fluoride, it is found that the lowest 3II state of SbI is repulsive, and a qualitative explanation for this distinction in terms of the electronegativity difference of the constituent atoms is put forward. The computer Te value of the a 1Δ2 state is in good agreement with a result inferred on the basis of experimental b 0+ and 1Δ2Te values in other group VA-VIIA and VIA-VIA systems. Two different semicore and full-core RECPs have been employed at various levels of sophistication in the spin-orbit CI treatment to obtain the present results and the corresponding findings are in generally good agreement with one another. The intensity of the b-X1 transition is computed to be much larger than that of b-X2, in agreement with the observations of Winter et al. The fact that the opposite relationship has been found for SbF and many other diatomics in which the halogen is the lighter of the two atoms, as first pointed out by Colin et al., is discussed and also found to be closely tied up with electronegativity considerations.