Knowledge Bank

This talk will present the PFI-ZEKE photoelectron spectra of two alkali metal-ether complexes: Li(DME) and Li(DXE); $DME=CH3OCH3,DXE=CH3O(CH2)2OCH3$. Both complexes were produced in a pulsed molecular beam and identified by time-of-flight mass spectrometry. The ZEKE spectra of these complexes show adiabatic ionization potentials and vibrational structures consisting of metal-ligand and ligand-based vibrations. The spectroscopic measurements were combined with density functional theory and Franck-Condon factor calculations to establish ground electronic states and geometries of the neutral and ionic species. For Li(DME), the neutral and ionic complexes were determined to be in $C2v$ symmetry with Li binding to oxygen. For Li(DXE), the Li atom binds to both oxygen atoms in a $C2$ five-membered ring structure, with the O-C-C-O dihedral angle of $\sim 50\circ$ in both the ion and neutral species. The ground electronic states of the DME complex and its ion are $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}A1$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}A1$, whereas those of the corresponding DXE complex and its ion are $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}A1$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}A$, respectively. Furthermore, the binding energies of the two neutral complexes were derived using a thermodynamic cycle. This simple calculation requires the ionization energies of the metal atom and complex as well as the dissociation energy of the cation complex.