RESUMEN
The amount of water vapor in the terrestrial atmosphere is highly variable both spatially and temporally. In the tropics it sometimes constitutes 4-5% of the atmosphere. At the same time collisional broadening of spectral lines by water vapor is much larger than that by nitrogen and oxygen. Therefore, in order to accurately characterize and model spectra of the atmospheres with significant amounts of water vapor, the line-shape parameters for spectral lines broadened by water vapor are required. In this work, the pressure-broadening parameters (and their temperature-dependent exponents) due to the pressure of water vapor for spectral lines of CO2, N2O, CO, CH4, O2, NH3, and H2S from both experimental and theoretical studies were collected and carefully reviewed. A set of semiempirical models based on these collected data was proposed and then used to estimate water broadening and its temperature dependence for all transitions of selected molecules in the HITRAN2016 database.
RESUMEN
The collisional widths of ~ 160 transitions belonging mainly to the 2nu(2)-nu(2), 3nu(2)-2nu(2), and 4nu(2)-3nu(2) hot bands of the H(2)(16)O molecule have been measured on Fourier-transform air-methane flame spectra at 2000 K and analyzed, showing a strong decrease in the collisional widths when the rotational quantum number J increases, as well as a nonnegligible decrease of the collisional widths when the nu(2) vibrational quantum number increases.
RESUMEN
We present here Fourier transform spectrometer measurements of the intensities of lines of (12)C(16)O(2) for the two bands centered at 720.2800 and 741.7243 cm(-1). In addition, a comparison is made to calculations using the direct numerical diagonalization method for these bands and other bands previously studied in the same spectral region. This comparison shows very good agreement (within a few percent).
RESUMEN
Intensities and broadening parameters of lines belonging to the 11101 ? 10002 band of (12)C(16)O(2) have been measured using Fourier transform spectroscopy spectra. From the measured line intensities it has been possible to determine the variation with respect to m or J of the squared transition dipole moment |micro|(2) as |micro|(2) = 1.323 x 10(-3) [1 + 1.0 x 10(-3) m - 1.6 x 10(-5)J (J + 1)](2) for P- and R-branches and |micro| = 1.323x10-5 J(J(2) = 1.323 x 10(-3) [1 - 3.5 x 10(-3)[1 - 3.5 x 10-5] J(J + 1)](2) for the Q-branch. Moreover, self-, nitrogen-, and oxygen-broadening parameters have been measured and they are compared with previously published values.
RESUMEN
A description and summary of the latest edition of the AFGL HITRAN molecular absorption parameters database 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 halfwidth, the temperature dependence of the air-broadened halfwidth, and the transition probability. The database contains 348043 entries between 0 and 17,900 cm(-1). 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 eleven heavy molecular species, applicable for qualitative simulation of transmission and emission in the atmosphere, has also been provided.
RESUMEN
Halfwidth and pressure-induced line shifts for ozone perturbed by nitrogen have been calculated using the quantum Fourier transform theory with improved dynamics (QFT-ID). All unique rotational transitions from J = 1 to 35 present on the AFGL main gas atlas (4852 transitions) have been considered. The halfwidth as a function of J, Ka, and transition type is considered for the first time over a full range of these quanta. Comparison with experiment shows the QFT-ID results for the halfwidth to be accurate to 5-10%. No corresponding measurements of the line shift have been made, hence the accuracy of the line shift is unknown; they can be used, however, for predicting trends.
RESUMEN
The latest edition of the AFGL atmospheric absorption line parameters compilation for the seven most active infrared terrestrial absorbers is described. Major modifications to the atlas for this edition include updating of water-vapor parameters from 0 to 4300 cm(-1), improvements to line positions for carbon dioxide, substantial modifications to the ozone bands in the middle to far infrared, and improvements to the 7- and 2.3-microm bands of methane. The atlas now contains approximately 181,000 rotation and vibration-rotation transitions between 0 and 17,900 cm(-1). The sources of the absorption parameters are summarized.
RESUMEN
A new compilation of methane line parameters for the 4136-4666-cm(-1) region has been obtained using experimental positions and intensities combined with known quantum assignments from the literature. Positions and intensities measured directly from the observed spectrum by computer are reported with accuracies of +/-0.0005 cm(-1) and 2%, respectively, for single unblended absorptions.
RESUMEN
Molecular vibration and rotation constants are obtained for the metastable a(1)Delta(g) electronic state of molecular oxygen. The constants are given for the u = 0 and u = 1 vibrational levels by combining recent high-resolution laboratory measurements with high-resolution observatory-based planetary and solar spectra of the magnetic dipole transitions of the system a(1)Delta(g) ? X(3)Sigma(-)(g).
RESUMEN
A new version of the AFGL atmospheric absorption line parameters compilation is now available. Major modifications since the last edition of 1978 include the updating of the strongest bands of water vapor, updated line positions for carbon dioxide, improved ozone parameters in the 5- and 10-microm regions, and updated and additional data for methane in the 3.5- and 7.7-microm regions. The atlas now contains over 159,000 rotational and vibration-rotation transitions from 0.3 to 17,880 cm(-1).
RESUMEN
New line parameters of the methane spectrum have been incorporated in the AFGL compilation for the 2385-3200-cm(-1) region and were determined from data recorded at 0.01- and 0.02-cm(-1) resolution. Observed line positions and strengths are given for approximately 8076 absorptions with strengths >3.3 x 10(-24) cm/molecule (8.2 x 10(-5) cm(-2) atm(-1)). Lower state energies are given for 97% of the absorptions listed. Most of the lower states are determined through assignment of seven bands of (12)CH(4) (nu(1), nu(3), 2nu(2), nu(2) + nu(4), 2nu(4), nu(3) + nu(4) - nu(4) and nu(2) + nu(3) - nu(2)), four bands of (13)CH(4) (nu(3), 2nu(4), nu(2) + nu(4) and nu(3) + nu(4) - nu(4)), and three bands of CH(3)D (nu(1), nu(4), and 2nu(5)). A few of the lower state energies are determined experimentally from the data taken at cold sample temperatures.
RESUMEN
A new edition of the AFGL trace gas compilation is now available. Absorption line parameters of positions, intensities, and halfwidths are given for the major bands of thirteen gases covering the spectral region from 0 to 10,000 cm(-1). In addition to updating the original gases (NO, SO(2), NO(2), and NH(3)), the molecules HNO(3), OH, HF, HC1, HBr, HI, CIO, OCS, and H(2)CO have been added to the compilation. The sources for the additions and modifications are described.
RESUMEN
Updated tables of vibrational energy levels, molecular constants, band origins, and intensities for carbon dioxide in the infrared region of the spectrum are presented. These tables are references for the AFGL Atmospheric Absorption Line Parameters Compilation.