Engineering Papers⌕ Search

Engineering topics

Toth, R. A.

Publications and source records attributed to Toth, R. A..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

The HITRAN 2008 Molecular Spectroscopic Database

This paper describes the status of the 2008 edition of the HITRAN molecular spectroscopic database. The new edition is the first official public release since the 2004 edition, although a number of crucial updates had been made available online since 2004. The HITRAN compilation consists of several components that serve as input for radiative-transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e., spectra in which the individual lines are not resolved; individual line parameters and absorption cross sections for bands in the ultra-violet; refractive indices of aerosols, tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for forty-two molecules including many of their isotopologues.

Rothman, Laurence S.↗
NASA NTRS2006

Line Mixing in Water Vapor and Methane

A multispectrum fitting algorithm has been used to identify line mixing and determine mixing parameters for infrared transitions of H2O and CH4 in the 5-9 micrometer region. Line mixing parameters at room temperature were determined for two pairs of transitions in the v2 fundamental band of H2O-16, for self-broadening and for broadening by H2, He, CO2, N2, O2 and air. Line mixing parameters have been determined from air-broadened CH4 spectra, recorded at temperatures between 210 K and 314 K, in selected R-branch manifolds of the v4 band. For both H2O and CH4, the inclusion of line mixing was seen to have a greater effect on the retrieved values of the line shifts than on the retrieved values of other parameters

Smith, M. A. H.↗
NASA NTRS2006

Air-Broadening of H2O as a Function of Temperature: 696 - 2163 cm(exp -1)

The temperature dependence of air-broadened halfwidths are reported for some 500 transitions in the (000)-(000) and (010)-(000) bands of H2(16)O using gas sample temperatures ranging from 241 to 388 K. These observations were obtained from infrared laboratory spectra recorded at 0.006 to 0.011 cm(exp-1) resolution with the McMath-Pierce Fourier transform spectrometer located at Kitt Peak. The experimental values of the temperature dependence exponents, eta, were grouped into eight subsets and fitted to empirical functions in a semi-global procedure. Overall, the values of eta were found to decrease with increasing rotational quantum number J. The number of measurements (over 2200) and transitions (586) involved exceeds by a large margin that of any other comparable reported study.

Toth, R. A.↗
NASA NTRS1995

The 1995 Atmospheric Trace Molecule Spectroscopy (ATMOS) Linelist

The Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment uses a Fourier transform spectrometer on board the space shuttle to record infrared solar occultation spectra of the atmosphere. Described are the current version of the molecular spectroscopic database used for the analysis of the data obtained during three Space Shuttle missions between 1992 and 1994.

molecular database↗
NASA NTRS1995

High Resolution Wavenumber Standards for the Infrared. (IUPAC Recommendations 1995)

The calibration of high resolution infrared spectra is generally more precise than accurate. This is the case even when they are recorded with Fourier transform interferometers. This presentation aims at improving the accuracy of wavenumber measurements in the infrared by recommending a selection of spectral lines as wavenumber standards for absolute calibration.

Interferometers Infrared Spectra Wavenumbers Fouri↗
NASA NTRS1993

The v 1 -v 2 , v 3 -v 2 , v 1 , and v 3 bands of H 2 16 O: line positions and strengths

High-resolution spectra of H 2 16 O were recorded with a Fourier-transform spectrometer covering transitions in the (100)-(010), (001)-(010), (100)-(000), and (001)-(000) bands. The measured line frequencies were used to determine high accuracy values of rotational energy levels in the (100) and (001) vibrational states. The experimental results provide a more accurate representation of the line positions and strengths than those presently available for these bands.

Fourier-transform↗
NASA NTRS1991

Stratospheric profiles of heavy water vapor isotopes and CH3D from analysis of the ATMOS Spacelab 3 infrared solar spectra

The isotopic composition of stratospheric water vapor and methane was investigated. Stratospheric profiles of HDO, (H-18)2O, (H-17)2O, and CH3D were derived from solar occultation spectra recorded on April 30 - May 1, 1985 by the Atmospheric Trace Molecule Spectroscopy Fourier transform spectrometer aboard Spacelab 3. The profiles of the three water-vapor isotopes showed an increase in the volume mixing ratio with altitude. The measured profiles of D/H in water vapor showed a large depletion in the lower stratosphere (about 63 percent relative to standard mean ocean water, SMOW, at 20 km) and a small increase in D/H with altitude at higher altitudes, up to 34 km. The D/H ratio in stratospheric methane was close to the corresponding isotopic ratio in SMOW.

Rinsland, C. P.↗
NASA NTRS1987

Molecular line parameters for the atmospheric trace molecule spectroscopy experiment

During its first mission in 1985 onboard Spacelab 3, the ATMOS (atmospheric trace molecule spectroscopy) instrument, a high speed Fourier transform spectrometer, produced a large number of high resolution infrared solar absorption spectra recorded in the occultation mode. The analysis and interpretation of these data in terms of composition, chemistry, and dynamics of the earth's upper atmosphere required good knowledge of the molecular line parameters for those species giving rise to the absorptions in the atmospheric spectra. This paper describes the spectroscopic line parameter database compiled for the ATMOS experiment and referenced in other papers describing ATMOS results. With over 400,000 entries, the linelist catalogs parameters of 46 minor and trace species in the 1-10,000/cm region.

Brown, L. R.↗
NASA NTRS1987

The HITRAN database - 1986 edition

A description and summary of the latest edition of the AFGL high-resolution transmission molecular absorption database (HITRAN) parameters are presented. This new database combines the information for the seven principal atmospheric absorbers and twenty-one additional molecular species previously contained on the AFGL atmospheric absorption line parameter compilation and on the trace gas compilation. In addition to updating the parameters on earlier editions of the compilation, new parameters have been added to this edition such as the self-broadened half-width, the temperature dependence of the air-broadened half-width, and the transition probability. The database contains 348,043 entries between 0 and 17,900/cm. A FORTRAN program is now furnished to allow rapid access to the molecular transitions and for the creation of customized output. A separate file of molecular cross sections of 11 heavy molecular species, applicable for qualitative simulation of transmission and emission in the atmosphere, has also been provided.

Rothman, L. S.↗