Vibrational Spectroscopy and Structural Analysis of V(CH) Clusters ( = 1-4).

The vibrational structure and binding motifs of vanadium cation-ethane clusters, V(CH), for = 1-4 are probed using infrared photodissociation spectroscopy in the C-H stretching region (2550-3100 cm). Comparison of spectra to scaled harmonic frequency spectra obtained using density functional theory suggests that ethane exhibits two primary binding motifs when interacting with the vanadium cation: an end-on η configuration and a side-on configuration. Determining the denticity of the side on isomer is complicated by the rotational motion of ethane, implying that structural analysis based solely on Born-Oppenheimer potential energy surface minimizations is insufficient and that a more sophisticated vibrationally adiabatic approach is necessary to interpret spectra.

Spectroscopy and fragmentation of undercoordinated bromoiridates.

We report gas-phase electronic photodissociation spectra of the undercoordinated bromoiridate complexes IrBr(4)(-) and IrBr(5)(-) at photon energies from 1 to 5.6 eV. Both ions have open-shell ground states with low-symmetry structures.

Gas-phase experiments on Au(III) photochemistry.

Irradiation of AuCl(4)(-) and AuCl(2)(OH)(2)(-) in the gas-phase using ultraviolet light (220-415 nm) leads to their dissociation. Observed fragment ions for AuCl(4)(-) are AuCl(3)(-) and AuCl(2)(-) and for AuCl(2)(OH)(2)(-) are AuCl(2)(-) and AuClOH(-). All fragment channels correspond to photoreduction of the gold atom to either Au(II) or Au(I) depending on the number of neutral ligands lost.

Microhydration of nitromethane anions from both a solute and solvent perspective.

We present experimental infrared spectroscopic data on mass-selected, hydrated nitromethane anion clusters with up to four water ligands. The vibrational bands in the OH stretching region encode the solvent structure, while the CH stretching bands contain information on the influence of the hydration shell on the solute ion. We interpret our findings using density functional theory calculations.

Electronic photodissociation spectra and decay pathways of gas-phase IrBr6(2-).

We report photodissociation action spectra for the dianion IrBr(6)(2-) in the range of 1.08-5.6 eV.

Photodamage to isolated mononucleotides--photodissociation spectra and fragment channels.

UV excitation of isolated singly-charged deprotonated mononucleotide anions in the gas phase can lead to their dissociation. We present mass spectrometry results, photodepletion and photofragment action spectra on the UV-photodissociation of deprotonated 2'-deoxyribonucleobase-5'-monophosphates with adenine, cytosine, guanine and thymine as nucleobases. We observe the same anionic fragments as in earlier experiments on collision-induced dissociation, although their relative intensities are quite different, especially with respect to the abundance of the deprotonated base anions.