DFT calculations of Ti-based molecules clustering with Ar for laser-based enrichment of stable isotopes

Abstract

Within PRISMAP, the European medical radionuclides program, we are investigating the possible enrichment of titanium and calcium stable isotopes by means of Separation of Isotopes by Laser Assisted Retardation of Condensation (SILARC). Titanium or calcium-containing molecules are injected in a gas cell containing argon as a buffer gas and released via a nozzle creating a supersonic jet. The temperature drops to ∼15K, at which point argon atoms cluster around the molecules. If an isotopomer can be selectively excited by an infrared laser, the clusterization can be prevented and the molecule experiences a drag force through the jet, physically separating it from the clusters.As a first step in this development, Density Functional Theory (DFT) calculations have been performed on titanium-containing molecules, to determine the ground-state configuration of the molecules (geometry and spin state), their interaction with Ar, and to calculate the frequencies of their vibrational modes as a function of Ti isotope. Isotope-selective transitions were identified, mostly in the mid-infrared region. In this contribution, the results from those calculations for simple molecules (TiFx (x=1−4)) and complex molecules (Ti[OEt]4, Ti[OPr]4, C10H2TiF12O4) are reported.