Contribution of thermal noise to the line width of Josephson radiation from superconducting point contacts
Contribution of thermal noise to line width of Josephson radiation from superconducting point contacts
Kamper, R. A.↗
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Natural line widths of Moessbauer absorbers of variable low temperatures.
Clamping system for maintaining natural line widths of Mossbauer absorbers at varying temperatures
Dash, J. G.↗
An Empirical Expression for Line Widths of Ammonia from Far-Infrared Measurements
The hydrogen- and self-broadened line widths of 116 (sup 14)NH(sub 3) ground state transitions with J,K = 1,0 to 10,10 have been measured at 0.0006 cm(sup -1) resolution using a Bruker spectrometer between 40 to 210 cm(sup -1). These experimental widths have been reproduced to 2.4% and 11% respectively using an heuristically derived expression of the form....
remote sensing planets↗
The solar O III spectrum. II - Longer wavelengths, line widths, and the He II Lyman alpha radiation field
The solar O III spectrum above 900 A is analyzed, including several visible and infrared lines which are important in nebular studies. The dependence of the line intensities on the rate of photoexcitation by He Ly-alpha is determined, and the observability of these lines in the solar spectrum is studied. The impact approximation is employed to calculate the expected line widths of the stronger solar O III lines. The photoexciting field at 304 A calculated from the observed intensities of the O III lines below 900 A (Bhatia et al., 1982) is compared with the field predicted by a recent model (Avrett et al., 1976). It is shown that additional radiation trapping must be present beyond that given by this model.
Kastner, S. O.↗
Contribution of thermal noise to the line- width of Josephson radiation from superconducting point contacts.
Voltage-biased superconducting point contact Josephson radiation line width investigation for thermal noise contributions useful for low temperature thermometer
ELECTRIC CONTACT↗
Diatomic predissociation line widths
Predissociation by rotation and curve crossing in diatomic molecules is discussed. The pattern of predissociation line widths is seen as providing a highly sensitive yardstick for the determination of unknown potential curves. In addition, the computation of such a pattern for given potential curves is considered a matter of routine, unless the predissociation happens to occur from an adiabatic potential curve. Analytic formulas are used to provide physical insight into the details of the predissociation pattern, to the extent that a direct inversion procedure is developed for determination of the repulsive potential curves for Type 1 predissociations.
Child, M. S.↗
An estimate of line width and pressure from the high resolution spectrum of Jupiter at 11,000 angstrom units
Pressure and line width estimate from high resolution image tube spectra of Jupiter at 11,000 A
Farmer, C. B.↗
Intensity and line width measurements in the nu(u) fundamental band of (C-13)H4
Intensities and collision-broadened line widths have been measured in the nu(u) fundamental band of (C-13)H4 at 295 K, employing the Doppler-limited spectral resolution of a tunable diode laser spectrometer and a (C-13)-enriched sample of CH4, H2, He, Ar, N2, O2, and air were chosen as the broadening gases in order to provide the data needed in atamospheric and planetary atamospheric applications.
Varanasi, Prasad↗
Diode laser measurements of CO line widths at planetary atmospheric temperatures
A tunable diode laser spectrometer and the sweep integration technique were used to measure hydrogen-broadened half-widths and nitrogen-broadened half-widths of eight lines between P(1) and P(15) in the CO fundamental at several temperatures between 94 and 298 K. The results are of interest in connection with studies of the atmospheres of earth, Jupiter, Saturn, and Titan.
Varanasi, P.↗
Measurements of 2p-1s line widths in low-Z pionic atoms
High-resolution lithium-drifted silicon and germanium detectors for measuring line widths of 2p-1s transitions in low-Z pionic atoms
Harris, R. J., Jr.↗
X-ray line widths and coronal heating
Preliminary results of spectroscopy and imaging of a solar active region and flare plasma in soft X-ray emission lines are presented. Observed X-ray line widths in a nonflaring active region are broader than the Doppler width corresponding to the local electron temperature. An analysis of 41 soft X-ray flares within a single active region reveals a preference for flares to occur at locations that already show enhanced X-ray emission and to favor magnetic complexity over high gradient. However, flares do not appear to be directly responsible for the heating and X-ray production of the active regions.
Acton, L. W.↗
Average effects of large-scale convection on helioseismic line widths and frequencies
The formalism of Lavely and Ritzwoller (1992) is here applied to the model of stationary large-scale solar convection developed by Glatzmaier (1984) in order to determine a characteristic giant-cell convection signature in helioseismic data. Frequency and line-width measurements are presented on spatially filtered spectra, so that references to azimuthal orders apply to the m-value of the spatial filter's spherical harmonic. Attention is given to the 'Q-bowl' pattern of large-scale convection, a systematic, apparent line-broadening.
Lavely, Eugene M.↗
Effects of line width and spatial extent on measurements of the 0.51 MeV Galactic center line
Over the past 15 years, a number of measurements have been made of positron-electron annihilation radiation from the Galactic Center region. The results after 1979 show a significant decrease in measured flux intensity from that previously observed with the same instruments. This is probably due to time variations; however, the contributions of a spatially extended and/or energy-broadened component should also be considered. The entire data set is consistent with a time variable point source plus a distribution along the Galactic Disk. There is no strong evidence for a component broadened in energy.
Dunphy, P. P.↗
N2 pressure - broadened O3 line widths and strengths near 1129.4 cm-1
A Beer's Law experiment was performed with a tunable diode laser to find the N2 pressure broadening characteristics of a single 03 absorption line at 1129.426 cm for N2 pressures from 10 to 100 torr (O3 pressure = 3.16 torr). SO2 line positions were used for wavelength calibration. Line shapes were interatively fitted to a Lorentz function. Results were delta (HWHM in MHz) = 47.44 (+ or - 5.34) MHz + 1.730 (+ or - 0.088) MHz/torr *p(torr) with sigma = 0.9897. This intercept compares well with the Doppler O3 - O3 broadened (at 3.16 torr) width of 44.52 Hz. This result in a HWHM line width of 0.44 cm atm at 760 torr and 285 K. The line strengths integrated over delta nu = 0.55 cm were found to be N2 pressure dependent.
Copeland, G. E.↗
An Empirical Expression for Line Widths of Ammonia From Far-Infrared Measurements
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Ammonia line widths far-infrared measurements Bruk↗
Measurements of Band Intensities, Herman-Wallis Parameters, and Self-Broadening Line-Widths of the 30011 - 00001 and 30014 - 00001 Bands of CO2 at 6503 cm(exp -1) and 6076 cm(exp -1)
Rotationless band intensities and Herman-Wallis parameters are listed in HITRAN tabulations for several hundred CO2 overtone-combination bands. These parameters are based on laboratory measurements when available, and on DND calculations for the unmeasured bands. The DND calculations for the Fermi interacting nv(sub 1) + v(sub 3) polyads show the a(sub 2) Herman-Wallis parameter varying smoothly from a negative value for the first member of the polyad to a positive value for the final member. Measurements of the v(sub 1) + v(sub 3) dyad are consistent with the DND calculations for the a(sub 2) parameter, as are our recent measurements of the 4v(sub 1) + v(sub 3) pentad. However, the measurement-based values in the HITRAN tables for the 2v(sub 1) + v(sub 3) triad and the 3v(sub 1) + v(sub 3) tetrad do not support the DND calculated values for the a(sub 2) parameters. We therefore decided to make new measurements to improve some of these intensity parameters. With the McMath FTS at Kitt Peak National Observatory/National Solar Observatory we recorded several spectra of the. 4000 to 8000 cm(exp -1) region of pure CO2 at 0.011 cm(exp -1) resolution using the 6 meter White absorption cell. The signal/noise and absorbance of the first and fourth bands of the 3v(sub 1) + v(sub 3) tetrad of C-12O-16 were ideal on these spectra for measuring line intensities and broadening widths. Our selfbroadening results agree with the HITRAN parameterization, while our measurements of the rotationless band intensities are about 15% less than the HITRAN values. We find a negative value of a(sub 2) for the 30011-00001 band and a positive value for the 30014-00001 band, whereas the HITRAN values of a(sub 2) are positive for all four tetrad bands. Our a(sub 1) and a(sub 2) Herman-Wallis parameters are closer to DND calculated values than the 1992 HITRAN values for both the 30011-00001 and the 30014-00001 band.
Giver, L. P.↗
A very high resolution study of emission line widths in Galactic and extragalactic H II regions
Very high spectral resolution spectroscopy was performed using the 5007-A forbidden O III line on two Galactic H II regions (NGC 6611 and NGC 7000) and three giant extragalactic H II regions (NGC 588, NGC 604, and IC 133) in M33. Use of the thermally narrow forbidden O III line also aided in the determination of the broadening due to mass motion, although the results are in agreement with the average values obtained in earlier studies primarily done with H-alpha. Evidence is confirmed and found for multiple velocity components in each of the extragalactic systems.
O'Dell, C. R.↗
Temperature-Dependence of Air-Broadened Line Widths and Shifts in the nu3 Band of Ozone
The 9.6-micron bands of O3 are used by many remote-sensing experiments for retrievals of terrestrial atmospheric ozone concentration profiles. Line parameter errors can contribute significantly to the total errors in these retrievals, particularly for nadir-viewing. The McMath-Pierce Fourier transform spectrometer at the National Solar Observatory on Kitt Peak was used to record numerous high-resolution infrared absorption spectra of O3 broadened by various gases at temperatures between 160 and 300 K. Over 30 spectra were analyzed simultaneously using a multispectrum nonlinear least squares fitting technique to determine Lorentz air-broadening and pressure-induced shift coefficients along with their temperature dependences for selected transitions in the 3 fundamental band of (16)O3. We compare the present results with other measurements reported in the literature and with the ozone parameters on the 2000 and 2004 editions of the HITRAN database.
Smith, Mary A. H.↗