Presentation description

The actinide halides and other small d-block element-containing molecules are difficult to model computationally due to electron correlation and relativistic effects such as spin-orbit coupling. Consequently, precise benchmarking of these molecules is needed to accurately model the bonding of M-X bonds. One such benchmark is the bond dissociation energy (BDE). We have measured the BDEs of various actinide halides to a high precision with an uncertainty of ~0.01 eV using resonant two-photon ionization spectroscopy, in which tunable lasers are scanned over a wavelength until a predissociation threshold in the target molecule is reached, at which point the molecule can jump to a dissociative continuum through various pathways. The molecule then falls apart and a drop to baseline in the molecular signal is observed. The particular species of interest, UCl, UBr, UI, ThCl, ThBr, and ThI are excellent candidates for BDE measurements using this method due to the high density of electronic states. The BDEs of these molecules can also be used to elucidate periodic trends in bonding.