109 research outputs found
``COMPLETE'' GROUND STATE ROTATIONAL CONSTANTS OF FROM PERTURBATION ALLOWED TRANSITIONS IN THE BAND
No full text Supported by the Monticello Foundation administered by the California Institute of Technology. C. Chackerian, JR., and G. Guelachvili, J. Mol. Spectrosc. 84, 447-456 (1980).Author Institution:The highly accurate ground state constants previously from an analysis of allowed transitions in the band are augmented with values for and . The latter were determined via ground state combination differences between allowed and perturbation allowed transitions in the parallel and perpendicular components of the band. These ground state differences were obtained for levels with and
CONCENTRATION INDEPENDENT ABSOLUTE INTENSITY DETERMINATIONS:A NEW METHOD
No full text J. R. Oppenhelimer, Proc. Cambridge Phil. Soc. 23, 327 (1926). Address of Chackerian: NASA Ames Research Center, MS:245-6, Moffett Field, CA 94035.Author Institution:We discuss some general considerations for obtaining, independently of any information on molecular concentration, absolute intensity determinations from relative molecule. This new method exploits the effect, first elucidated sixty years , which vibration-rotation interaction has on relative rovibrational line intensities in a vibrational band. This approach is important for vibrational fundamental bands of diatomic molecules since they cannot be studies by the lifetime method which requires the radiative relaxation lifetime to be much shorter than competing collisional relaxation processes. Our new method should be particularly significant for diatomic radical species whose concentrations can be inferred only indirectly
HCL FUNDAMENTAL ROVIBRATIONAL SELF-BROADENING COEFFICIENTS BETWEEN 200K AND 300K
No full text C. Chackerian, Jr. and G. Guelachvili, J. Mol. Spectrosc. 97, 316 (1983).Author Institution: Astrophysical Experiments Branch, NASA Ames Research CenterThe temperature dependence of the HCL vibrational fundamental self-broadening is obtained from high resolution Fourier spectra using the direct retrieval . The temperature dependence of the broadening is explained in terms of a simple ``two component'' phenomenological model
``ANOMALOUS'' RO-VIBRATIONAL INTENSITIES IN THE BANDS OF
No full text J.B. Burkholder, P.D. Hammer, C.J. Howard, A.G. Maki, G. Thompson, and C. Chackerian, Jr., J. Mol. Spectrosc. 124, 137 (1987). C. Chackerian, Jr., G. Guelachvili, A. Lopez-Pineiro. and R.H. Tipping, J. Chem. Phys. 90. 641 (1989). D.D. Nelson, Jr., A. Schiffman, D.J. Nesbitt and J.D. Yaron, J. Chem. Phys. (to be published).Author Institution: Laboratoire d'Infrarouge, Universite de Paris-Sud.; Laboratoire d'Infrarouge, NASA-Ames Research CenterRelative line Intensities of p- and r- branch transitions of diatomic radical molecules (ClO, NH, OH) have recently1-3 been used along with the theory of the Herman-Wallis effect to obtain estimates of electric dipole vibrational transition moments. Of the first and second row diatomic hydrides, ab initio calculations predict SH to exhibit the largest H.W. effect. Indeed, our spectra confirm a very large effect, and we present here an attempt at a quantitative analysis of the Herman-Wallis intensity perturbation in SH
ABSOLUTE RO-VIBRATIONAL INTENSITIES FOR THE VIBRATIONAL BANDS OF
No full text C. Chackerian. Jr. J Chem Phys 85, 1200 (1986) C. Chackerian. Jr. C. W Bauschlicher, S. R. Langhoff. A. Lopes-Pineiro and R. H. Tipping (to be published)Author Institution: NASA-Ames Research Center, Moffett Field; Leboratotre d'lnfrarouge associ\'e au CNRS, Universit\'e de Paris-sud; Departmento de Outmica Fisica, Facultad de Ciencias, Universided de Extremedura; Department of Physics and Astronomy, University of AlabamaWe determine absolute ro-vibrational line intensities for vibrational bands of the astrophysically important species. NH, indepently of any information on its molecular concentration. To this end we measure relative line intensities across bends. The effect of vibration rotation interaction on the line intensities then allows a direct determination of the derivative of the electric-dipole fundamental band transition . The results of these experiments are then compared to theoretical obtained via high quality ab initu calculations of the electric dipole moment function
TEMPERATURE-DEPENDENCE OF AIR-BROADENING AND SHIFTS OF LINES
No full text. M. N. Spencer, C. Chackerian, C. Flannery, and J.I. Steinfeld, Spectrochim. Acta 48A, 1273-1282 (1992). 2. M. N. Spencer, C. Chackerian, C. Flannery, and J.I. Steinfeld, J. Quant. Spectrosc. Radiat. Transfer, in press (1993).Author Institution: Atmospheric Sciences Division, NASA Langely Research Center; Department of Physics, The College of William and MaryWe have recorded high-resolution absorption spectra of ozone broadened by dry air at several temperatures between and using the Fourier transform spectrometer at the McMath-Pierce facility of the National Solar Observatory on Kitt Peak. The spectra cover the region from approximately to at a resolution of . Broadening gas pressures varied from approximately 100 to 250 Torr. From these spectra we have determined air-broadening and line shift coefficients and their temperature dependences for a number of lines in the band. The broadening results are compared with previous measurements of the temperature-dependence of and broadening coefficients in the . Analysis of additional lines in the , and bands is in progress
NEW INFRARED FREQUENCY AND INTENSITY MEASUREMENTS ON CHLORINE MONOXIDE (C10)
No full textAddress of Burkholder, Hammer, and Howard,: NDAA Environmental Research Laboratories, 325 Broadway, Boulder, CO 80303. Address of Maki and Thompson: Molecular Spectroscopy Division, National Bureau of Standards, Gaithersburg, MD 20899. Address of Chackerian: NASA Ames Research Center, Moffett Field, CA 94035.Author Institution:A Fourier transform spectrometer and tunable diode laser have been used to measure the wavenumbers and relative intensities of the entire 1-0 vibrational band of C10, including both and transistions for both chlorine isotopes. Measurements of the transitions of the 2-0 band of have also been made. Improved rovibrational constants will be given along with improved values for the energy levels and infrared transition frequncies. The Herman-Wallis term describing the rotational dependence of the intensity has been determined from relative line intensity measurements made across the band. From this term it has been possible to determine the 1-0 transition moment and intergrated band intensity without measuring C10 concentration
COLLISIONAL LINE MIXING IN THE BRANCH OF THE 5 BAND OF
No full textAuthor Institution: Laboratoire de Spectrochimie Mol{\'e}culaire, Universit{\'e} Pierre et Marie Curie, Bat. F., 4 Place Jussieu; Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.; NASA Ames Research Center, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.; L.P.M.A., Universit\'{e} de Paris-Sud, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.The transitions of the band of between 1459.5 and show the effects of line mixing in the resolution spectra recorded with the FTS at Kitt Peak National Observatory/National Solar Observatory. The line mixing has been modelled in the self-broadened spectrum of methyl choloride using the MEG (Modified Exponential Gap) law for scaling inelastic rates. The effect, on the mixing, of different collisional selection rules has been investigated. The line positions, intensities and have been measured for the brach for J = 0 - 37 of using four low pressure (0.2 to 0.7 Torr) and four higher pressure (8 to 23 Torr) spectra. The accuracies are for the positions, for intensities and for widths. The self-broadened line widths vary from 0.582 to . These measurements have been used to validate the line parameters used in the calculations and to obtain the parameter in the MEG scaling law
Rydberg-Klein-Rees 1-Sigma-positive potential curve turning points for the isotopes of carbon monoxide
No full textFirst order RKR turning points were computed for (C-12)O16, (C-12)O17, (C-13)O16, (C-12)O18, and (C-13)O18 for vibrational levels up to v = 40. These turning points should be useful in the numerical computation of matrix elements of powers of the internuclear separation
INTENSITY AND POSITION MEASUREMENTS OF CARBON DIOXIDE LINES IN THE 4370 TO 4640 REGION
No full textAuthor Institution: NASA AMES Research Center, , MS 245/4, Moffett Field, CA 94035-1000.B. Bezard, C. de Bergh, D. Crisp, and J.-P. Maillard, Nature 245, 508 (1990). C. R. Pollock, F.R. Petersen, D. A. Jennings, and J. S. Wells, J. Mol. Spectrosc. 99, 357 (1983).A set of 14 spectra of the carbon dioxide absorption bands in the 4300 to 4700 region were obtained with a BOMEM DA3.002 FTS and a White cell using absorption path lengths between 507 and 1307 meters. The principal purpose of this work was to make the first laboratory measurements of the transition moment and Herman-Wallis intensity parameters of the band at . This weak band was recently found to be prominent in the thermal emission spectrum of the dark side of . Our measured rotationless transition moment of this band is . Line positions for this band were calibrated using the 2-0 of CO. The spectra of CO and were recorded simultaneously with a small amount of added CO to the . In this spectral region we have also recorded data which is suitable for intensity and positional work on the , and bands of and the band of
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