Activation of CO by Actinide Cations (Th, U, Pu, and Am) as Studied by Guided Ion Beam and Triple Quadrupole Mass Spectrometry.

Reactions of CO with Th have been studied using guided ion beam tandem mass spectrometry (GIBMS) and with An (An = Th, U, Pu, and Am) using triple quadrupole inductively coupled plasma mass spectrometry (QQQ-ICP-MS). Additionally, the reactions ThO + CO and ThO + CO were examined using GIBMS. Modeling the kinetic energy-dependent GIBMS data allowed the determination of bond dissociation energies (BDEs) for (Th-O) and (OTh-O) that are in reasonable agreement with previous GIBMS measurements.

Bond energies of ThO(+) and ThC(+): A guided ion beam and quantum chemical investigation of the reactions of thorium cation with O2 and CO.

Kinetic energy dependent reactions of Th(+) with O2 and CO are studied using a guided ion beam tandem mass spectrometer. The formation of ThO(+) in the reaction of Th(+) with O2 is observed to be exothermic and barrierless with a reaction efficiency at low energies of k/kLGS = 1.21 ± 0.

Activation of Methane by Os : Guided-Ion-Beam and Theoretical Studies.

Activation of methane by the third-row transition-metal cation Os is studied experimentally by examining the kinetic energy dependence of reactions of Os with CH and CD using guided-ion-beam tandem mass spectrometry. A flow tube ion source produces Os in its electronic ground state and primarily in the ground spin-orbit level. Dehydrogenation to form [Os,C,2 H] +H is exothermic, efficient, and the only process observed at low energies for reaction of Os with methane, whereas OsH dominates the product spectrum at higher energies.

Thermochemistry of alkali metal cation interactions with histidine: influence of the side chain.

The interactions of alkali metal cations (M(+) = Na(+), K(+), Rb(+), Cs(+)) with the amino acid histidine (His) are examined in detail. Experimentally, bond energies are determined using threshold collision-induced dissociation of the M(+)(His) complexes with xenon in a guided ion beam tandem mass spectrometer. Analyses of the energy dependent cross sections provide 0 K bond energies of 2.

Infrared multiple photon dissociation spectroscopy of cationized histidine: effects of metal cation size on gas-phase conformation.

The gas phase structures of cationized histidine (His), including complexes with Li(+), Na(+), K(+), Rb(+), and Cs(+), are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy utilizing light generated by a free electron laser, in conjunction with quantum chemical calculations. To identify the structures present in the experimental studies, measured IRMPD spectra are compared to spectra calculated at B3LYP/6-311+G(d,p) (Li(+), Na(+), and K(+) complexes) and B3LYP/HW*/6-311+G(d,p) (Rb(+) and Cs(+) complexes) levels of theory, where HW* indicates that the Hay-Wadt effective core potential with additional polarization functions was used on the metals. Single point energy calculations were carried out at the B3LYP, B3P86, and MP2(full) levels using the 6-311+G(2d,2p) basis set.

Guided ion beam and theoretical study of the reactions of Os+ with H2, D2, and HD.

Reactions of the third-row transition metal cation Os(+) with H(2), D(2), and HD to form OsH(+) (OsD(+)) were studied using a guided ion beam tandem mass spectrometer. A flow tube ion source produces Os(+) in its (6)D (6s(1)5d(6)) electronic ground state level. Corresponding state-specific reaction cross sections are obtained.

Guided ion beam and theoretical study of the reactions of Au+ with H2, D2, and HD.

Reactions of the late third-row transition metal cation Au(+) with H(2), D(2), and HD are examined using guided ion beam tandem mass spectrometry. A flow tube ion source produces Au(+) in its (1)S (5d(10)) electronic ground state level. Corresponding state-specific reaction cross sections for forming AuH(+) and AuD(+) as a function of kinetic energy are obtained and analyzed to give a 0 K bond dissociation energy of D(0)(Au(+)-H) = 2.

Vibrational spectroscopy and theory of Fe(+)(CH(4))(n) (n = 1-4).

Vibrational spectra are measured for Fe(+)(CH(4))(n) (n = 1-4) in the C-H stretching region (2500-3200 cm(-1)) using photofragment spectroscopy. Spectra are obtained by monitoring CH(4) fragment loss following absorption of one photon (for n = 3, 4) or sequential absorption of multiple photons (for n = 1, 2). The spectra have a band near the position of the antisymmetric C-H stretch in isolated methane (3019 cm(-1)), along with bands extending >250 cm(-1) to the red of the symmetric C-H stretch in methane (2917 cm(-1)).

Vibrational spectroscopy of intermediates in methane-to-methanol conversion by FeO(+).

Gas phase FeO(+) can convert methane to methanol under thermal conditions. Two key intermediates of this reaction are the [HO-Fe-CH(3)](+) insertion intermediate and Fe(+)(CH(3)OH) exit channel complex. These intermediates are selectively formed by reaction of laser-ablated Fe(+) with organic precursors under specific source conditions and are cooled in a supersonic expansion.

Methane activation by cobalt cluster cations, Co(n)+ (n = 2-16): reaction mechanisms and thermochemistry of cluster-CH(x) (x = 0-3) complexes.

The kinetic energy dependences of the reactions of Co(n)(+) (n = 2-16) with CD(4) are studied in a guided ion beam tandem mass spectrometer over the energy range of 0-10 eV. The main products are hydride formation, Co(n)D(+), dehydrogenation to form Co(n)CD(2)(+), and double dehydrogenation yielding Co(n)C(+). These primary products decompose to form secondary and higher order products, Co(n)CD(+), Co(n-1)D(+), Co(n-1)C(+), Co(n-1)CD(+), and Co(n-1)CD(2)(+) at higher energies.

Direct determination of the ionization energies of PtC, PtO, and PtO2 with VUV radiation.

Photoionization efficiency curves were measured for gas-phase PtC, PtO, and PtO2 using tunable vacuum ultraviolet (VUV) radiation at the Advanced Light Source. The molecules were prepared by laser ablation of a platinum tube, followed by reaction with CH4 or N2O and supersonic expansion. These measurements provide the first directly measured ionization energy for PtC, IE(PtC) = 9.

Mode selective photodissociation dynamics in V+(OCO).

The electrostatic V+(OCO) complex has a vibrationally resolved photodissociation spectrum in the visible. Photodissociation produces V+ + CO2 (nonreactive pathway) and VO+ +CO (reactive pathway). Production of VO+ is energetically favored, but spin forbidden.

Electronic and vibrational spectroscopy and vibrationally mediated photodissociation of V+(OCO).

Electronic spectra of gas-phase V+(OCO) are measured in the near-infrared from 6050 to 7420 cm(-1) and in the visible from 15,500 to 16,560 cm(-1), using photofragment spectroscopy. The near-IR band is complex, with a 107 cm(-1) progression in the metal-ligand stretch. The visible band shows clearly resolved vibrational progressions in the metal-ligand stretch and rock, and in the OCO bend, as observed by Brucat and co-workers.