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  • 11
    Electronic Resource
    Electronic Resource
    The relationship between science and technology
    Amsterdam : Elsevier
    Research Policy 23 (1994), S. 477-486 
    Details
    ISSN: 0048-7333
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Economics , Nature of Science, Research, Systems of Higher Education, Museum Science
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0048-7333(94)01001-3
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  • 12
    Electronic Resource
    Electronic Resource
    The molecular Stark effect in regions of high state density: Overall simplicity and underlying complexity in the response to a static electric field (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 6210-6220 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present the high-resolution (11 MHz) infrared measurement of the molecular Stark effect for the R(0) transition of the acetylenic C–H stretch in 2-propyn-1-ol. The field-free spectrum is fragmented into three eigenstate components due to the effects of intramolecular vibrational energy redistribution (IVR). As the field strength increases from 0 to 25 kV/cm, the number of eigenstates increases linearly. The center-of-gravity of the fragmented R(0) transition follows the simple, second-order Stark shift (Δν∝E2) expected for the bright state. However, when viewed at the eigenstate level, the mechanism of the Stark shift is rather complex. At lower field strengths, the eigenstates shift in energy, as occurs for Stark effects in lower state density regimes. As the number of coupled states increases, energy shifting of the eigenvalues is quenched. To preserve the second-order Stark shift of the center-of-gravity, the intensity "rolls over'' the largely rigid eigenvalue structure. For molecules in regions of high state density, the reduced energy shifting of the eigenvalues as the electric field is increased means that lack of deflection by inhomogeneous electric fields is not necessarily a consequence of the molecule being nonpolar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467084
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  • 13
    Electronic Resource
    Electronic Resource
    Sub-Doppler, infrared laser spectroscopy of the propyne 2ν1 band: Evidence of z-axis Coriolis dominated intramolecular state mixing in the acetylenic CH stretch overtone (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 2596-2611 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The eigenstate-resolved 2ν1 (acetylenic CH stretch) absorption spectrum of propane has been observed for J'=0–11 and K=0–3 in a skimmed supersonic molecular beam using optothermal detection. Radiation near 1.5 μm was generated by a color center laser allowing spectra to be obtained with a full-width at half-maximum resolution of 6×10−4 cm−1 (18 MHz). Three distinct characteristics are observed for the perturbations suffered by the optically active (bright) acetylenic CH stretch vibrational state due to vibrational coupling to the nonoptically active (dark) vibrational bath states. (1) The K=0 states are observed to be unperturbed. (2) Approximately 2/3 of the observed K=1–3 transitions are split into 0.02–0.25 cm−1 wide multiplets of two to five lines. These splittings are due to intramolecular coupling of 2ν1 to the near resonant bath states with an average matrix element of 〈V2〉1/2=0.002 cm−1 that appears to grow approximately linearly with K. (3) The K subband origins are observed to be displaced from the positions predicted for a parallel band, symmetric top spectrum.The first two features suggest that the coupling of the bright state to the bath states is dominated by parallel (z-axis) Coriolis coupling. The third suggests a nonresonant coupling (Coriolis or anharmonic) to a perturber, not directly observed in the spectrum, that itself tunes rapidly with K; the latter being the signature of diagonal z-axis Coriolis interactions affecting the perturber. A natural interpretation of these facts is that the coupling between the bright state and the dark states is mediated by a doorway state that is anharmonically coupled to the bright state and z-axis Coriolis coupled to the dark states. Z-axis Coriolis coupling of the doorway state to the bright state can be ruled out since the ν1 normal mode cannot couple to any of the other normal modes by a parallel Coriolis interaction. Based on the range of measured matrix elements and the distribution of the number of perturbations observed we find that the bath levels that couple to 2ν1 do not exhibit Gaussian orthogonal ensemble type statistics but instead show statistics consistent with a Poisson spectrum, suggesting regular, not chaotic, classical dynamics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.466456
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  • 14
    Electronic Resource
    Electronic Resource
    Nuclear Radiation Effects in Solids (1956)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Nuclear and Particle Science 6 (1956), S. 215-276 
    Details
    ISSN: 0066-4243
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ns.06.120156.001243
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  • 15
    Electronic Resource
    Electronic Resource
    Resources and the Quality of Life in 2000 (1978)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Materials Research 8 (1978), S. 1-20 
    Details
    ISSN: 0084-6600
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ms.08.080178.000245
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  • 16
    Electronic Resource
    Electronic Resource
    United States Energy Alternatives to 2010 and Beyond: The Conaes Study (1979)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Environment and Resources 4 (1979), S. 1-70 
    Details
    ISSN: 0362-1626
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.eg.04.110179.000245
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  • 17
    Electronic Resource
    Electronic Resource
    DECODING THE DYNAMICAL INFORMATION EMBEDDED IN HIGHLY MIXED QUANTUM STATES (2000)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physical Chemistry 51 (2000), S. 323-353 
    Details
    ISSN: 0066-426X
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract The standard description of the vibrational and rotational motion of polyatomic molecules, as expressed by the distortable rotor/harmonic oscillator approximation, provides an adequate description of the molecular quantum states only in regions of low total state density. When the total state density is large, exceeding 100 states/cm-1, the vibrational dynamics are "dissipative" and the fundamental process of intramolecular vibrational energy redistribution is operative. The presence of intramolecular vibrational energy redistribution leads to molecular quantum states of a qualitatively different nature. With respect to a normal-mode vibrational basis, these quantum states are "highly mixed" in their vibrational character and represent nuclear motion that is a combination of all the normal-mode motions. This review describes frequency domain spectroscopy techniques designed to probe the vibrational, rotational, and structural composition of these eigenstates. Recent work that investigates spectroscopy between highly mixed states is also reviewed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.physchem.51.1.323
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  • 18
    Electronic Resource
    Electronic Resource
    Reinvestigation of the acetylenic C–H stretching fundamental of propyne via high resolution, optothermal infrared spectroscopy: Nonresonant perturbations to ν1 (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 2588-2595 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present the high resolution spectrum of the ν1 fundamental of propyne near 3335 cm−1 obtained using a very warm free jet expansion in our optothermal detection spectrometer. By using a high concentration sample expanded at low backing pressures we have been able to observe transitions for K values up to K=6. The additional data available allow us to reinvestigate this vibrational band. We find an unusual perturbation pattern in this band where the individual subbands (rovibrational transitions for a single K value) appear to be completely unperturbed at the level of precision of our data (7.5 MHz), but the subband origin orderings are perturbed through nonresonant interactions. Attempts to account for the subband ordering using a two-state anharmonic interaction are unsuccessful indicating that the perturbations are of multistate origin. This type of nonresonant perturbation to the subband origins of symmetric top molecules should be a common feature of symmetric tops with large A rotational constants. As a result of this investigation we conclude that the previously reported value of αA, determined from a very cold expansion where only K=0 and K=1 were observed, is not a measure of the true (unperturbed) value of this constant. This conclusion is also supported by force field calculations presented here that use an empirical harmonic force field augmented by diagonal anharmonicities for the hydride stretches. These calculations, which reproduce measured values of αA and αB for lower energy bands quite successfully, also show that the previous determination of αA is too large and must be dominated by perturbation contributions. We have also measured the weak Fermi resonant band ν3+2ν09 which acquires its intensity through interaction with ν1. Again we find an anomalous subband ordering like that observed in ν1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.466455
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  • 19
    Electronic Resource
    Electronic Resource
    The rotational spectrum of a highly vibrationally mixed quantum state. II. The eigenstate-resolved spectroscopy analog to dynamic nuclear magnetic resonance spectroscopy (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 1990-1999 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The description of the rotational spectrum of a single molecular eigenstate in an energy region where conformational isomerization can occur is presented. The conformational isomerization rate can be determined from an analysis of the overall line shape of the spectrum. The isomerization dynamics are investigated through a time-domain analysis. It is shown that the nonstationary state produced by coherent microwave excitation has a well-defined conformational structure. However, the individual molecular eigenstates are a mixture of rovibrational states associated with the two conformations. The structural localization decays to the eigenstate equilibrium value at a rate defined as the isomerization rate. It is also shown that the line shape of the spectrum coalesces as the isomerization rate exceeds the difference between the characteristic rotational frequencies of the two conformers. The line shape profile of the eigenstate-resolved spectrum is well described by the Bloch equations modified for chemical exchange. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477864
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  • 20
    Electronic Resource
    Electronic Resource
    Intramolecular vibrational energy redistribution in the acetylenic C–H and hydroxyl stretches of propynol (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 4316-4326 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The high-resolution infrared spectra of the acetylenic C–H and O–H stretches of propynol have been measured using an electric-resonance optothermal molecular beam spectrometer (EROS). Both spectra display extensive fragmentation of the hydride-stretch oscillator strength characteristic of the intramolecular vibrational energy redistribution (IVR) process. The IVR lifetime is strongly mode-specific. The IVR lifetime of the acetylenic C–H stretch is approximately 400 ps, with a slight increase in the lifetime with increasing values of the Ka quantum number. The lifetime of the O–H stretch is 60 ps and is independent of the rotational quantum numbers. The experimental upper limit for the anharmonic state densities are 30 and 40 states/cm−1 for the acetylenic C–H and O–H stretches, respectively. These values are in good agreement with the values obtained by a direct state count (19 and 32 states/cm−1, respectively). The measured density of states increases with an approximate (2J+1)-dependence. These results indicate that all energetically accessible states are involved in the IVR dynamics. However, neither the acetylenic C–H nor the O–H stretch shows a decrease in lifetime as the total angular momentum (J) increases. This result shows that Coriolis coupling of these two hydride stretches to the near-resonant bath states is much weaker than the anharmonic coupling. For the O–H stretch, we are able to obtain the root-mean-squared (rms) matrix element for the Coriolis coupling prefactor, 0.0015(5) cm−1. The rms anharmonic coupling matrix element is 0.03 cm−1. For the low J values measured in the O–H spectrum, the Coriolis-induced IVR rate is much slower than the initial redistribution rate resulting from the stronger anharmonic interactions leading to an IVR process with two distinct time scales. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477075
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