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We report on the motional and proton transfer dynamics of the super photobase FR0-SB in the series of normal alcohols C1 (methanol) through C8 (n-octanol) and ethylene glycol. Steady-state and time-resolved fluorescence data reveal that the proton abstraction dynamics of excited FR0-SB depend on the identity of the solvent and that the transfer of the proton from solvent to FR0-SB*, forming FR0-HSB+*, fundamentally alters the nature of interactions between the excited molecule and its surroundings. In its unprotonated state, solvent interactions with FR0-SB* are consistent with slip limit behavior, and in its protonated form, intermolecular interactions are consistent with a much stronger interaction of FR0-HSB+* with the deprotonated solvent RO–. We understand the excited-state population dynamics in the context of a kinetic model involving a transition state wherein FR0-HSB+* is still bound to the negatively charged alkoxide, prior to solvation of the two charged species. Data acquired in ethylene glycol confirm the hypothesis that the rotational diffusion dynamics of FR0-SB* are largely mediated by solvent viscosity while proton transfer dynamics are mediated by the lifetime of the transition state. Taken collectively, our results demonstrate that FR0-SB* extracts solvent protons efficiently and in a predictable manner, consistent with a ca. 3-fold increase in dipole moment upon photoexcitation as determined by ab initio calculations based on the equation-of-motion coupled-cluster theory.

The utility of 22 density functionals paired with relativistic effective core potentials (RECPs) for the prediction of thermodynamic properties was investigated for the Ln54 set of lanthanide-containing molecules. The Ln54 set includes lanthanide oxides, fluorides, and chlorides with the lanthanide formally in the +1, + 2, or +3 oxidation state. The density functionals were chosen to span the gamut of complexity from the local density approximation to double hybrids. Computed enthalpies of formation and bond dissociation energies were compared to experimental data and to previous calculations performed with all electron basis sets. The performance of the functionals was then assessed for each class of molecules in the Ln54 set. Overall, SVWN was found to be the best-performing functional having the lowest MAD of 22.1 kcal mol and the most systematic deviation in comparison to the other functionals.

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The recently proposed idea of identifying the most important higher-than-doubly excited determinants in the ground-state coupled-cluster (CC) calculations through stochastic configuration interaction Quantum Monte Carlo propagations [J. E. Deustua et al., Phys. Rev. Lett. 119, 223003 (2017)] is extended to excited electronic states via the equation-of-motion (EOM) CC methodology. The advantages of the new approach are illustrated by calculations aimed at recovering the ground-and excited-state energies of the CH + molecule at the equilibrium and stretched geometries resulting from the EOMCC calculations with a full treatment of singles, doubles, and triples.