Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1573-9120
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1434-6079
    Keywords: PACS. 33.20.Ea Infrared spectra - 33.70.-w Intensities and shapes of molecular spectral lines and bands - 34.10.+x General theories and models of atomic and molecular collisions and interactions (including statistical theories, transition state, stochastic and trajectory models, etc.)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: Line mixing effects have been studied in the band of perturbed by helium. Theoretical absorption coefficients are compared to FTIR measurements, which were made at room temperature for helium pressure from 1 atm up to 90 atm. The observed strong modifications with respect to additive Lorentzian contributions are explained by line coupling effects. The Infinite Order Sudden Approximation and the Energy Corrected Sudden Approximation are used in order to account for these effects. The latter gives better agreement: it rather successfully predicts the band shape and the linewidths.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1562-6911
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The IR absorption spectrum of mixtures of CH4 with Kr in the range 800–6000 cm−1 is studied in the region of the gas-liquid and liquid-crystal phase transitions. It is found that, as the system density increases, the ratio of the ν4 band intensity to that of the ν3 band becomes larger and the measured values of the second spectral moment of the ν4 band become smaller than the corresponding calculated values. The quantum counterpart of the generalized J-diffusion model was used to describe the shape of the ν3 and ν4 bands, and the rotational relaxation times of CH4 in solutions were obtained. It was shown that, as the density increases, a broad 1470-cm−1 band appears in the region of the “forbidden” (induced by a Coriolis interaction) ν2 band (νQ=1535 cm−1) detected in a low-density gas. The intensity of this band is appreciably higher than that of the ν2 band.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: This study seeks to determine the origin of several features observed in the behavior at high j values of shift cross sections in the 0-0 and 0-1 bands of HF in a bath of argon. These features were not explained in earlier quantum mechanical calculations. A semi-classical (classical path) simplified formalism is used to demonstrate that shift cross sections depend sensitively on vibration-rotation coupling in the high j limit. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 108 (1998), S. 3608-3619 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A kinetic theory of spectral band shapes is developed which accounts for the effects of line mixing and finite duration of collisions. The theory is based on a projection operator technique with a nonorthogonal metric. The roles and hierarchy of various approximations commonly employed are analyzed. It is shown that the relaxation operator must be defined before the initial correlations are suppressed so that the double sum rule for the matrix elements of this operator is conserved. This conservation is important for the calculations of the wings of band shapes. Rotovibrational band shapes for some specific cases of Raman and infrared absorption spectra of gases are considered. The expressions obtained relate the band wing profiles with the spectral density of molecular torque arising from binary collisions. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 2067-2072 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: IR absorption beyond the head of the 0003–0000 (3ν3) band of CO2 near 7000 cm−1 has been analyzed. This absorption is found to consist of two comparable intensity contributions, namely, the allowed band wing and a collision-induced absorption (CIA) band. The band wing profile has been described by using a non-Markovian theory and the rotational perturbation densities for CO2–CO2 collisions, which was previously calculated from the intensity distribution in the high-frequency wing of the 0001–0000 CO2 band. The CIA component has a typical shape of CO2 CIA bands with the maximum at the double transition (0001+0002)–(0000+0000) frequency. The integrated binary coefficient of this CIA band was estimated to be B2=(1.0±0.6)×10−5 cm−2 Amagat−2. The CIA spectral moment theory has been used for the intensity calculation, which takes into account for the first time the collision-induced vibrational force field in CO2 pairs. By comparing the calculated and measured intensity for the double transition, the polarizability anisotropy matrix element for the 2ν3 band has been estimated as β20=0.26±0.08 a.u., value in reasonable agreement with an independent estimation from previous results of polarizability matrix elements of CO2. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...