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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 97 (1993), S. 52-58 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 10153-10167 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Formation of Ti+(H2)n clusters (n=1–6) has been studied by both temperature-dependent equilibrium measurements and density functional theory (DFT). The successive binding energies (BDEs) were measured to be 7.5±0.5, 9.7±0.6, 9.3±0.7, 8.5±0.4, 8.2±0.4, and 8.7±0.4 kcal/mol for n=1–6, respectively. The relatively low value of the n=1 BDE is due to a curve crossing from the Ti+[a4F(sd2)] ground state to the Ti+[b4F(d3)] first excited asymptote with the addition of the first ligand. The first BDE is 10 kcal/mol when measured with respect to the excited state asymptote. This series of almost constant BDEs is unlike any other M+(H2)n series. The present DFT calculations show these relatively constant BDE values for the Ti+(H2)n clusters are due to an electronic occupation which allows the Ti+ ion to interact equally with up to six H2 ligands. Bond lengths, geometries, and vibrational frequencies from the DFT calculations are reported here for all clusters. The influence of basis set size and computational method on the first two clusters was also examined. It was determined that a multireference wave function was required to describe these first two clusters accurately. A possible crossing to the lowest doublet potential energy surface was examined for Ti+(H2)4 and found to be endoergic. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 1121-1131 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: CHO+ ions are made by electron impact on CD3OH in the source (ICR1) of a tandem ion cyclotron resonance spectrometer. These ions are injected into a differentially pumped analysis cell (ICR2) where they are reacted with a number of small molecules. The internal energy distribution in the CHO+ ions is obtained using total reactivity studies with neutral molecules of varying proton affinities. About 40% of the CHO+ ions react with D2 either by proton transfer to form D2H+ or isotopic exchange to form CDO+ ions. A series of experiments are performed that conclusively show these ions are the HOC+ isomer and the exchange is due to the catalytic isomerization reaction HOC++D2→DCO++HD which is approximately 37 kcal/mol exothermic. The product DCO+ ions are vibrationally cool indicating the reaction releases most of its energy as kinetic energy. Absolute rate constants for reactions of CHO+ ions with the neutrals 13CO, 15N2, CO2, O2, D2, and Ar are reported. HOC+ reacts with D2 at about 30% of the collision rate. This rate decreases with increasing HOC+ kinetic energy in the range 0.025 to 0.44 eV. The two products of the reaction are D2H+/CO and DCO+/HD with DCO+/HD comprising ∼42% of the products for the HOC+ ions formed from CD3OH. Phase space theory calculations are performed to determine the barrier to catalytic isomerization. The data are best fit with a barrier between 0.0 and −0.05 eV relative to the HOC+/D2 asymptotic energy. A barrier of this magnitude yields reaction rate constants at interstellar temperatures of at least 10% of the collision rate constant (i.e., k〉1×10−10 cm3/s), and could explain why so little HOC+ is observed in interstellar clouds.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 4517-4523 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rate constants of the charge exchange reactions, CO2++ O2→O2++CO2 and O2++O2→O2+O2+ have been studied as a function of both the internal and kinetic energies of the reactant ion in a tandem ICR spectrometer. Primary ions with known internal energies are formed in the source of the tandem by charge transfer reactions whose energy partitioning has already been determined. The rate constant of the CO2++O2 reaction is found to be 4.4×10−11 cm3 s−1 for ground state primary ions and increases by a factor of 2.9 when CO2+ ions have 1.4 eV of internal energy; this reaction is also found to be much less sensitive to the kinetic energy of the parent ion than to its internal energy. The rate constant for the symmetric charge exchange reaction O2++O2 has been determined for internal energies corresponding approximately to the v=0, 3, and 9 vibrational levels of the O2+ ground electronic state and is found to increase with internal energy, at least at low collision energy.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 4849-4855 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The spin-forbidden radiative decays of the lowest energy metastable electronic states of O+2 and NO+ have been studied using a Fourier transform ion cyclotron resonance mass spectrometer. The metastable species are stored in the mass spectrometer for several hundreds of milliseconds and then selectively detected by pulsing CO2 into the ion trap and monitoring the formation of CO+2. By varying the delay time between formation of the metastable ions and injection of CO2, apparent radiative lifetimes of 101 ms for O+2(a 4Πu) and 530 ms for NO+(a 3Σ+) are measured. Our results are compared with literature values and with a theoretical calculation. The theoretical model, demonstrated for O+2, is based on spin–orbit coupling between the a 4Πu and A2Πu states and upon spin–rotation mixing of the different spin components within the a 4Πu state. The results allow quantitative interpretation of our results and those available in the literature.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Reduced zero field mobilities of Cr+, Co+, and Ni+ in their ground state configuration (3dn) and their metastable excited state configuration (3dn−14s1) have been measured in He and Ne as a function of temperature. Parameters for a n−6−4 interaction potential are obtained by fitting the mobility vs temperature curve. Bond dissociation energies, vibrational frequencies, and equilibrium bond lengths are extracted from these curves and compared with data from traditional equilibrium measurements and ab initio theory. Dramatic changes in bonding are observed for the 3dn and 3dn−14s1 configurations; the 3dn configuration yielding very much stronger bonds and very much shorter equilibrium bond lengths than the 3dn−14s1 configuration. The presence of multiple potential curves in the interaction of Co+(3F,3d8) and Ni+(2D,3d9) with He/Ne make interpretation of the ground state mobility data ambiguous. The analysis of each system is discussed in some detail.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 3835-3837 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A new method for identifying and characterizing cluster ion isomers is presented. Results indicate that most carbon clusters have more than one stable form, with 29≤n≤45 indicating three or four different structures. Fullerenes first appear at C+30 and begin to dominate above C+45. From small to large the isomeric progression is from linear to rings to fullerenes.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 116 (1994), S. 9710-9718 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 93 (1971), S. 5352-5358 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 90 (1986), S. 477-481 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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