Study of spin-orbit and electron correlation effects on molecules containing heavy elements and color-tuning of luminescent salen-aluminum complexes

Abstract

Quantum chemical calculations have been performed to confirm, improve the phenomenological assignments. Two-component spin-orbit density functional theory (SO-DFT) calculations for spectroscopic constants of chloroiodomethane and bromoiodomethane cations have been performed using shape-consistent relativistic effective core potentials (RECPs) with effective one-electron spin-orbit operator. Calculated vibrational frequencies of haloiodomethane cations $CH_2XI^+$ (X=Cl and Br) from conventional DFT calculations without spin-orbit interactions are not in agreement with experimental ones from mass-analyzed threshold ionization (MATI) experiments. While, calculated vibrational frequencies of haloiodomethane cations from SO-DFT calculations qualitatively agree well with experimental ones. Other halogen series of haloiodomethane cations $CH_2XI^+$ (X=F and I) were also calculated to compare the extent of spin-orbit effects on cations containing iodine elements. The reason for the dramatic spin-orbit effects on the geometries of $CH_2ClI^+$ were investigated from DFT and SO-DFT calculations of $CH_2XI$ (X=F, Cl, Br, and I) neutrals and cations. Structures and vibrational frequencies of group 17 fluorides EF_{3} (E= I, At, and element 117) are calculated from DFT and SO-DFT calculations to investigate the effects of spin-orbit interactions and electron correlations on the structures and vibrational frequencies of $EF_3$. Spin-orbit and electron correlation effects generally increase bond lengths and/or angles in both $C_{2v}$ and $D_{3h}$ structures. For $IF_3$, the $C_{2v}$ structure is a global minimum, and the $D_{3h}$ structure is a second-order saddle point in all performed calculations. Spin-orbit effects for $IF_3$ are negligible in comparison to electron correlation effects. The $D_{3h}$ global minimum is the only minimum structure for $(117)F_3$ in all RECP calculations, and the $C_{2v}$ structure is neither a local minimum nor a saddle point. In the case of...