- Gas-Phase Reactions of LaFe1+ with Alkanes
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The formation and reactions of LaFe1+ with saturated hydrocarbons are reported.Laser-generated La1+ reacts with iron pentacarbonyl to yield predominantly LaFe(CO)31+, which upon collisional activation yields LaFe1+/s
- Huang, Yongqing,Freiser, Ben S.
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- Heavy water reactions with atomic transition-metal and main-group cations: Gas phase room-temperature kinetics and periodicities in reactivity
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Reactions of heavy water, D2O, have been measured with 46 atomic metal cations at room temperature in a helium bath gas at 0.35 Torr using an inductively coupled plasma/selected ion flow tube tandem mass spectrometer. The atomic cations were produced at ca. 5500 K in an ICP source and were allowed to decay radiatively and thermalize by collisions with Ar and He atoms prior to reaction. Rate coefficients and product distributions are reported for the reactions of fourth-row atomic cations from K+ to Se+, of fifth-row atomic cations from Rb+ to Te+ (excluding Tc+), and of sixth-row atomic cations from Cs+ to Bi +. Primary reaction channels were observed leading to O-atom transfer, OD transfer, and D2O addition. O-Atom transfer occurs almost exclusively (≥90%) in the reactions with most early transition-metal cations (Sc+, Ti+, V+, Y+, Zr +, Nb+, Mo+, Hf+, Ta+, and W+) and to a minor extent (10%) with one main-group cation (As+). OD transfer is observed to occur only with three cations (Sr+, Ba+, and La+). Other cations, including most late transition and main-group cations, were observed to react with D 2O exclusively and slowly by D2O addition or not at all. O-Atom transfer proceeds with rate coefficients in the range of 8.1 × 10-13 (As+) to 9.5 × 10-10 (Y +) cm3 molecule-1 s-1 and with efficiencies below 0.1 and even below 0.01 for the fourth-row atomic cations V+ (0.0032) and As+ (0.0036). These low efficiencies can be understood in terms of the change in spin required to proceed from the reactant to the product potential energy surfaces. Higher order reactions are also measured. The primary products, NbO+, TaO+, MoO +, and WO+, are observed to react further with D 2O by O-atom transfer, and ZrO+ and HfO+ react further through OD group abstraction. Up to five D2O molecules were observed to add sequentially to selected M+ and MO+ as well as MO2+ cations and four to MO2D +. Equilibrium measurements for sequential D2O addition to M+ are also reported. The periodic variation in the efficiency (k/kc) of the first addition of D2O appears to be similar to the periodic variation in the standard free energy (ΔG°) of hydration.
- Cheng, Ping,Koyanagi, Gregory K.,Bohme, Diethard K.
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p. 8561 - 8573
(2008/10/09)
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- Reactions of laser-ablated Y and La atoms with H2O infrared spectra and density functional calculations of the HMO, HMOH and M(OH)2 molecules in solid argon
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Reactions of laser-ablated Y and La atoms with water molecules have been studied using matrix-isolation FTIR spectroscopy and density functional calculations. The reaction products were identified based on isotope labeled experiments and density functiona
- Zhang, Luning,Shao, Limin,Zhou, Mingfei
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- A new hypermetallic molecule LaOMn generated by laser ablation
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A new hypermetallic oxide LaOMn and its positive ion involving two heterometal atoms were observed and identified in the 532 nm laser ablation of a La0.67Ca0.33MnO3 target using both time-resolved quadrupole mass spectrometric and time-of-flight mass spectrometric techniques. The dependence of LaOMn+ yield on the laser fluence also confirmed the formation of the ionic hypermetallic species. Theoretical calculations were carried out to predict the stability and the geometric structures of these new molecules. The calculations suggest that the LaOMn and LaOMn+ molecules might be formed via secondary reactions of the neutral and ionic MnO with La or La+ in the laser ablated plasma.
- Wang, Xue-Feng,Dang, Hai-Jun,Gu, Zhen-Ning,Qin, Qi-Zong
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p. 739 - 744
(2008/10/08)
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- Gas-phase Metal Oxidation Reactions studied by Chemielectron Spectroscopy and Chemiion Mass Spectrometry: Reactions of Cerium and Lanthanum with O2(X 3Ζ-g), O2(a 1Δg) and O(3P)
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The gas-phase reactions M + O2(X3Ζ-g), M + O2(a 1Δg) and M + O(3P) have been studied with chemielectron spectroscopy, where M represents one of the lanthanide metals, cerium or lanthanum.Assignment of the observed bands has been assisted by mass analysis of the ions produced and by approximate kinetic modelling calculations.For the M + O2(X 3Ζ-g) and M + O2 (a 1Δg) associative ionization reactions, most of the excess energy appears as electron kinetic energy, whereas for the M + O(3P) reactions a larger fraction of the reaction energy is retained in the positive ion.
- Cockett, Martin C. R.,Dyke, John M.,Ellis, Andrew M.,Wright, Timothy G.
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