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  • 11
    Electronic Resource
    Electronic Resource
    Inelastic scattering of NO from Ag(111): Internal state, angle, and velocity resolved measurements (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 734-750 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have determined the velocity distributions of individual quantum states of NO scattering from Ag(111) at specific scattering angles θf using molecular beam techniques to control the incidence energy Ei and angle θi. We find that the mean energies of scattered species Ef depend weakly on θf at low collision energies, but become increasingly independent of this parameter as Ei approaches 1.0 eV. This is true for all final rotation states J. The previously reported insensitivity of the final kinetic energy to J is found to apply at all scattering angles, so that Ef vs θf curves for high J fall only slightly below those for low J. This system is highly translationally inelastic at high incidence energies, with up to 55% of Ei being lost to phonons at Ei=1.0 eV. Angular distributions are relatively insensitive to J at low Ei , but for high Ei the peak flux is found to shift away from the surface normal as Ei increases. The effect of the surface temperature only becomes apparent at low incidence energies. A search for supernumerary rotational rainbows reveals no discernible oscillations even for the lowest surface temperatures. We believe that these supernumerary oscillations may be damped by "surface corrugation'' effects for this system. Discussion focuses on the observed anticorrelation between kinetic energy transfer to phonons and to rotation, the extent to which parallel momentum is conserved in this system, and energy-angle scaling laws for energy transfer. In this latter case we show that energy transfer in this system scales approximately with the quantity Ei cos θi, over the full range of conditions covered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460342
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  • 12
    Electronic Resource
    Electronic Resource
    A critical examination of data on the dissociative adsorption and associative desorption of hydrogen at copper surfaces (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 7502-7520 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We examine experimental data on the activated dissociative adsorption and associative recombination of hydrogen at copper surfaces with respect to the role played by molecular vibrational states. We use models describing the variation of the adsorption probability with the vibrational state, kinetic energy, and angle of the incident molecules, establishing the parameters of the models by a nonlinear least squares fit to adsorption data. Using the principle of detailed balance, we apply these models to the corresponding data on associative desorption thus comparing adsorption data with desorption angular, velocity, and internal state distributions. The most consistent picture resulting from this analysis is that the adsorption has significant contributions from both H2(v=0) and H2(v=1) and that these components have markedly different translational thresholds. Within the framework of this picture we are able to resolve the apparent contradiction between the strong angular dependence of the kinetic energy required for adsorption and the lack of angular dependence of the mean kinetic energy of desorption. We also partially resolve the apparent discrepancy in interpretation of the role of H2(v=1) in recent adsorption experiments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460182
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  • 13
    Electronic Resource
    Electronic Resource
    Effect of incidence energy and angle on the adsorption probability of Xe on Pt(111): Energy–angle scaling relations (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 1942-1943 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The sticking probability of Xe on Pt(111) at a surface temperature of 85 K is found to fall rapidly with increasing kinetic energy over the range 63 to 800 meV. Increasing the incidence angle from 30° to 60° generally raises this probability, in a manner consistent with an approximate scaling with Ei cos1.6θi.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457051
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  • 14
    Electronic Resource
    Electronic Resource
    Quantum mechanical reaction probabilities with a power series Green's function (1993)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 98 (1993), S. 6917-6928 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present a new method to compute the energy Green's function with absorbing boundary conditions for use in the calculation of quantum mechanical reaction probabilities. This is an iterative technique to compute the inverse of a complex matrix which is based on Fourier transforming time-dependent dynamics. The Hamiltonian is evaluated in a sinc-function based discrete variable representation, which we argue may often be superior to the fast Fourier transform method for reactive scattering. We apply the resulting power series Green's function to the calculation of the cumulative reaction probability for the benchmark collinear H+H2 system over the energy range 0.37–1.27 eV. The convergence of the power series is found to be stable at all energies and accelerated by the use of a stronger absorbing potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.464759
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  • 15
    Electronic Resource
    Electronic Resource
    High-temperature supersonic molecular-beam source (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 3939-3943 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a supersonic molecular-beam source that can be heated to over 2300 K. Our design employs a commercially available tungsten tube which is resistively heated by passage of current along its length between two water-cooled copper clamps. The clamps are supported so as to minimize bending stresses on the tube while allowing for thermal expansion. Gas is supplied to the tube at one end using an o-ring connection and emerges from an orifice drilled about halfway along the length. The other end of the tube is welded closed. Temperature is measured by a thermocouple spot-welded adjacent to the orifice. The entire tube is surrounded by two tantalum heat shields which are split lengthwise for convenient assembly. These have large holes aligned with the beam axis. We present details of the design, assembly, and characterization of this source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143242
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  • 16
    Electronic Resource
    Electronic Resource
    Differential Effect of NMDA on Extracellular Serotonin in Rat Midbrain Raphe and Forebrain Sites (1996)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 66 (1996), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The contribution of NMDA receptors to regulation of serotonin (5-HT) release was assessed by in vivo microdialysis in freely behaving rats. During infusion of NMDA (30, 100, and 300 µM) into the dorsal raphe nucleus (DRN), 5-HT was increased by ∼25, 100, and 280%, respectively. Competitive and noncompetitive NMDA-receptor antagonists blocked this effect on DRN 5-HT. Infusion of NMDA (300 µM) into the DRN also produced an 80% increase in extracellular 5-HT in the nucleus accumbens. During infusion of NMDA (100 and 300 µM) into the median raphe nucleus (MRN), 5-HT was increased by ∼15 and 80%, respectively. NMDA-receptor antagonists blocked this effect on MRN 5-HT. Infusion of NMDA into the MRN also produced a significant increase in hippocampal 5-HT. In contrast, infusion of NMDA into the nucleus accumbens, frontal cortex, or hippocampus produced small decreases in 5-HT in these forebrain sites. Taken together, these results suggest that NMDA receptors in the midbrain raphe, but not the forebrain, can have an excitatory influence on 5-HT neurons and, thus, produce increased 5-HT release in the forebrain. Furthermore, in comparison with the MRN, DRN 5-HT neurons were more sensitive to the excitatory effect of NMDA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1996.66031067.x
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  • 17
    Electronic Resource
    Electronic Resource
    Increased Extracellular Serotonin in Rat Brain After Systemic or Intraraphe Administration of Morphine (1994)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 63 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The effect of morphine on serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in the CNS of unanesthetized rats was investigated by microdialysis. Morphine was administered either subcutaneously, by local perfusion into the diencephalon, or by intraraphe microinjection. Systemic administration of morphine resulted in a significant increase in both extracellular 5-HT and 5-HIAA in the diencephalon. The effect of morphine on 5-HT was dose dependent during local perfusion of the diencephalon with inhibitors of uptake or monoamine oxidase. Systemic morphine also produced significant increases in extracellular 5-HT in the striatum and hippocampus during uptake inhibition. The site of opioid effects on 5-HT was tested by locally perfusing morphine into the diencephalon. This had no effect on 5-HT or 5-HIAA. In contrast, intraraphe injection of morphine caused a dose-dependent increase in extracellular 5-HT and 5-HIAA in the diencephalon. These results suggest that systemic morphine induces an increase in 5-HT release in widespread areas of the forebrain. This appears to be due to an effect on 5-HT cell bodies and not on 5-HT nerve endings in projection sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.63020517.x
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  • 18
    Electronic Resource
    Electronic Resource
    AGE AND GENDER DIMENSIONS OF FRIENDSHIP (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Psychology of women quarterly 9 (1985), S. 0 
    Details
    ISSN: 1471-6402
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Psychology
    Notes: Since stereotypes about appropriate social behavior appear to influence questionnaires and other self-reported data concerning friendship, an in-depth interview format was used to explore gender and age differences in friendship patterns. Thirty-one subjects were interviewed: five young males, six young females, fivemidlife males, five midlife females, five older males, and five older females. As in our previous questionnaire studies, groups described friendship in superficially similar ways. However, in the taped interviews, large gender differences appeared that followed conceptually along instrumental/expressive dimensions. Women at all ages were more expressive in their friendships, showing higher levels of empathy and altruism than men. Age differences also appeared, with men developing increased concern and thoughtfulness in friendship with greater age, and women showing more tolerance and less confrontation of their friends with greater age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-6402.1985.tb00898.x
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  • 19
    Electronic Resource
    Electronic Resource
    First-row transition metal complexes of the hexadentate macrocycle 1,4,7-tris(5-tert-butyl-2-hydroxybenzyl)-1,4,7-triazacyclononane (LH3). Crystal structures of [LTiIV]BPh4, [LCrIII], [LFeIII], and [(LH)2FeIII2](ClO4)2.2H2O (1993)
    s.l. : American Chemical Society
    Inorganic chemistry 32 (1993), S. 508-519 
    Details
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ic00057a005
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  • 20
    Electronic Resource
    Electronic Resource
    The Acid Anhydride Character of Aspirin (1953)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 75 (1953), S. 5984-5986 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja01119a062
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