Structure Determination of Zinc and Cadmium Dication Complexes with Intact and Deprotonated Histidyl Glycine and Glycyl Histidine Dipeptides.

Metalated intact and deprotonated histidyl glycine and glycyl histidine dipeptides were investigated in the gas phase by using infrared multiple photon dissociation (IRMPD) spectroscopy with light from a free-electron laser (FEL). The dipeptides M(GlyHis), M(HisGly), [M(GlyHis-H)], and [M(HisGly-H)], where M = Zn and Cd, were probed to elucidate how the His position along the peptide chain and ligand charge state might influence the structures observed in the gas phase. Simulated annealing calculations were performed to determine energetically low-lying conformers and isomers of these structures.

Enthalpy of the Cerium (Ce) Chemi-Ionization Reaction and CeO, CeC, and CeCO Bond Energies Determined by Energy-Resolved Guided Ion Beam Mass Spectrometry Experiments.

Cerium (Ce) oxide, carbide, and carbonyl cation bond energies and the exothermicity of the Ce chemi-ionization (CI) reaction with atomic oxygen were investigated using guided-ion beam tandem mass spectrometry (GIBMS). The kinetic energy dependent product cross sections for reactions of Ce with O, CO, and CO and CeO with O, CO, Xe, and Ar were measured using GIBMS. For the reactions of Ce with O and CO, CeO is formed through an exothermic reaction, whereas CeO formation is endothermic in the reaction with CO.

Guided Ion Beam Studies of the Dy + O → DyO + e Chemi-ionization Reaction Thermochemistry and Dysprosium Oxide, Carbide, Sulfide, Dioxide, and Sulfoxide Cation Bond Energies.

Guided ion beam tandem mass spectrometry (GIBMS) was used to measure the kinetic energy dependent product ion cross sections for reactions of the lanthanide metal dysprosium cation (Dy) with O, SO, and CO and reactions of DyO with CO, O, and Xe. DyO is formed through an exothermic process when Dy reacts with O, whereas all other processes observed are found to be endothermic. The kinetic energy dependences of these cross sections were analyzed to yield 0 K bond dissociation energies (BDEs) for DyO, DyC, DyS, DyO, and DySO.