Jahn-Teller distortions in the photodetachment spectrum of PtCl6(2-): a four-component relativistic study.

In this work the mutual influence of Jahn-Teller (JT) and spin-orbit effects on the photoelectron spectrum of PtCl(6)(2-) is analyzed. For this purpose potential energy surfaces of PtCl(6)(-) along the JT active modes are calculated in the four-component Dirac-Coulomb (DC) framework and the possible JT stabilizations are determined. For the relativistic calculation we set out from the one-particle propagator implemented on the basis of the DC Hamiltonian. A correlated four-component approach is favorable for complexes with a strongly relativistic central atom due to the complicated interplay of electron correlation and relativity. PtCl(6)(2-) possesses a long enough lifetime which makes it amenable to precise experimental measurements. In the photoelectron spectrum of PtCl(6)(2-) some peaks could not be unambiguously assigned either originating from a JT splitting or representing individual spin-orbit components. In previously calculated dianionic tetrahalide platinum complexes PtX(4)(2-) (X = F,Cl,Br) it was observed that spin-orbit effects dominate over the d-orbital-induced JT effects. The same trend also persists in the currently studied hexachlorocomplex where sizable platinum-induced spin-orbit splittings give rise to features that supersede any JT structures.