All-electron double zeta basis sets for platinum: Estimating scalar relativistic effects on platinum(II) anticancer drugs

Segmented all-electron contracted double zeta valence plus polarization function (DZP) basis sets for the element Pt were constructed for use in conjunction with the non-relativistic and Douglas-Kroll-Hess (DKH) Hamiltonians. The DZP-DKH set is loosely contracted and thus offer computational advantages compared to the generally contracted relativistic basis sets, while their sufficiently small size allows it to be used in place of effective core potentials (ECP) for routine studies of molecules. Using the one-parameter hybrid functional mPW1PW, the performance of the basis sets is assessed for predicting the molecular structures and atomic charges of platinum(II) antitumor drugs, cisplatin and carboplatin. These results can be used as reference values to calibrate further ECP calculations. Despite their compact size, the DZP sets demonstrate consistent, efficient, and reliable performance and will be especially useful in calculations of molecular properties that require explicit treatment of the core electrons.