587 research outputs found
A calibration line list for 807-1167 cm -1 from high resolution Fourier spectroscopy of the 14NH3 nu sub 2 band
A calibration list of 295 lines observed over the 800 to 1170 cm to the -1 power region is presented. This list is intended for use as a calibration reference for calibrating diode laser spectra. The transition frequencies were calibrated against the well established laser frequencies of CO2. The estimated uncertainty in the corrected frequencies is + or - 1x.0001 cm to the -1 power
Lifetimes, transition probabilities, and level energies in Fe I
We use time-resolved laser-induced fluorescence to measure the lifetime of 186 Fe levels with energies between 25 900 and 60 758 cm . Measured emission branching fractions for these levels yield transition probabilities for 1174 transitions in the range 225-2666 nm. We find another 640 Fe transition probabilities by interpolating level populations in the inductively coupled plasma spectral source. We demonstrate the reliability of the interpolation method by comparing our transition probabilities with absorption oscillator strengths measured by the Oxford group [Blackwell et al., Mon. Not. R. Astron. Soc. 201, 595-602 (1982)]. We derive precise Fe level energies to support the automated method that is used to identify transitions in our spectra
Argon I lines produced in a hollow cathode source, 332 nm to 5865 nm
We report precision measurements by
Fourier transform spectroscopy of the
vacuum wavenumber, line width, and relative
signal strength of 928 lines in the
Ar I spectrum. Wavelength in air and classification
of the transition are supplied for
each line. A comparison of our results with
other precision measurements illustrates
the sensitivity of Ar I wavelengths to conditions
in the light source
A facility for high resolution spectroscopy: Laboratory and ground based observations in support of upper atmospheric research
This research task consists of operating a facility for making spectroscopic observations in support of upper atmospheric research. The facility responds to the needs and interests of the visiting investigators. Therefore, the research objectives are not predetermined except in broad outline. The emphasis is on studies that take advantage of the particular strengths of the Fourier Transform Spectrometer on Kitt Peak: high spectral resolution combined with wide spectral range and low noise
The 12 micron band of ethane: A spectral catalog from 765 cm(-1) to 900 cm(-1)
The high resolution laboratory absorption spectrum of the 12 micro band of ethane gas is studied. The data were obtained using the McMath Solar Telescope 1 meter Fourier Transform interferometer at Kitt Peak National Observatory and tunable diode laser spectrometers at the University of Tennessee and NASA/Goddard Space Flight Center. Over 200 individual vibration rotation transitions were analyzed taking into account many higher order effects including torsional splitting. Line positions were reproduced to better than 0.001/cm. Both ground and upper state molecular constants were determined in the analysis. The experimental details, the analysis procedures and the results are addressed. A list of ethane transitions occurring near (14)CO2 laser lines needed for heterodyne searches for C2H6 in extraterrestrial sources is also included. A spectral catalog of the ethane nu sub g fundamental from 765/cm to 900/cm is provided. A high dispersion (1/cm 12 in.) plot of both the Kitt Peak interferometric data and a simulated spectrum with Doppler limited resolution, a table of over 8500 calculated transitions listed quantum number assignments, frequencies and intensities are provided
Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes
A solar photospheric "thermal profiling" analysis is presented, exploiting
the infrared rovibrational bands of carbon monoxide (CO) as observed with the
McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above
the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum
intensities and center-limb behavior constrained the temperature profile of the
deep photosphere, while CO center-limb behavior defined the thermal structure
at higher altitudes. The oxygen abundance was self consistently determined from
weak CO absorptions. Our analysis was meant to complement recent studies based
on 3-D convection models which, among other things, have revised the historical
solar oxygen (and carbon) abundance downward by a factor of nearly two;
although in fact our conclusions do not support such a revision. Based on
various considerations, an oxygen abundance of 700+/-100 ppm (parts per million
relative to hydrogen) is recommended; the large uncertainty reflects the model
sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O,
and 18O.Comment: 90 pages, 19 figures (some with parts "a", "b", etc.); to be
published in the Astrophysical Journal Supplement
Argon I lines produced in a hollow cathode source, 332 nm to 5865 nm
We report precision measurements by
Fourier transform spectroscopy of the
vacuum wavenumber, line width, and relative
signal strength of 928 lines in the
Ar I spectrum. Wavelength in air and classification
of the transition are supplied for
each line. A comparison of our results with
other precision measurements illustrates
the sensitivity of Ar I wavelengths to conditions
in the light source
Southern Galactic Plane Survey Measurements of the Spatial Power Spectrum of Interstellar H I in the Inner Galaxy
Using data from the Southern Galactic Plane Survey we have measured the
spatial power spectrum of the interstellar neutral atomic hydrogen in the
fourth Galactic quadrant. This function shows the same power law behavior that
has been found for H I in the second quadrant of the Milky Way and in the
Magellanic Clouds, with the same slope. When we average over velocity intervals
broader than the typical small-scale velocity dispersion, we find that the
slope steepens, from approx. -3 to -4 for the warm gas, as predicted by
theories of interstellar turbulence if the column density fluctuations are
dominated by variations in the gas density on small spatial scales. The cool
gas shows a different increase of slope, that suggests that it is in the regime
of turbulence dominated by fluctuations in the velocity field. Overall, these
results confirm that the small scale structure and motions in the neutral
atomic medium are well described by a turbulent cascade of kinetic energy.Comment: 20 pages with 8 figures, LaTeX. Accepted by Ap. J. (scheduled for ApJ
Vol. 561 num. 2, November 10, 2001
- …