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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Absolute integrated intensity for the nu-1 sulfur dioxide band

The absolute integrated intensity of the IR vibration-rotation nu-1 SO2 band was measured using the linear portion of the curve of growth. Infrared spectroscopic-absorption cell measurements were performed on sulfur dioxide at partial pressures less than 0.15 torr with nitrogen added to give a total pressure of 705 torr, the path length being 4 mm. The absolute integrated intensity was determined to be 112.0 plus or minus 2.6/cm/sq (atm cm) at 296 K at the 95% confidence level.

Pilon, P. J.↗
NASA NTRS1977

Absorption strength measurement of the nu-1 band of methyl chloride

The absorption strengths of the Q-branch manifolds of the nu-1 band of methyl chloride were measured. The results were used to deduce the band strength, which is 32.1 plus or minus 2.9 per sq cm-atm at 297 K. The P-branch absorptions were investigated to assess the possibility of determining a vibration-rotation factor for the band. This factor is approximately 1.026.

Margolis, J. S.↗
NASA NTRS1978

Identification of the nu-2 vibration-rotation band of ammonia in ground level solar spectra

Comparison of infrared solar spectra in the 750 to 950 kayser region obtained during sunrise and sunset shows that a number of features due to the nu-2 NH3 band are present on the sunset spectra but are indicated by only a trace on the sunrise spectra. The sunset path shows approximately 0.007 atm-cm NH3, and the reason for the discrepancy between sunrise and sunset spectra is not known. The ground-based measurements at Denver were obtained with a 0.06 kayser resolution.

Murcray, D. G.↗
NASA NTRS1979

A vectorization of the Hess McDonnell Douglas potential flow program NUED for the STAR-100 computer

The computer program NUED for analyzing potential flow about arbitrary three dimensional lifting bodies using the panel method was modified to use vector operations and run on the STAR-100 computer. A high speed of computation and ability to approximate the body surface with a large number of panels are characteristics of NUEDV. The new program shows that vector operations can be readily implemented in programs of this type to increase the computational speed on the STAR-100 computer. The virtual memory architecture of the STAR-100 facilitates the use of large numbers of panels to approximate the body surface.

Boney, L. R.↗
NASA NTRS1979

On the CH4 nu-4 fundamental controversy - Line-intensity measurements revisited

Because of the controversy over the value of the band strength for the nu-4 fundamental of CH4, equivalent widths of the R(0), R(1), and P(11, 11, F1) lines have been measured to compare with opposing views. The present measurements are consistent with the band strength of Ko and Varanasi (1977), who, on the basis of high-resolution line-strength measurements, propose an integrated band strength of 145 kaysers/(cm-am).

Lutz, B. L.↗
NASA NTRS1983

Identification of forbidden transitions in the nu-4 band of (N-14)H3 by intracavity laser-Stark spectroscopy

These transitions are forbidden in the sense that they follow the selection rule delta K = + or - 2, which violates the usual rule that delta K = + or - 1 for a perpendicular band of a symmetric top, where K is the projection of the total angular momentum onto the molecular symmetry axis. The assignments are based for the most part on laser-Stark measurements made with a CO laser and an intracavity Stark cell. The procedure followed in making the assignments is described. Attention is called to the significance of these new lines in the analysis of the nu-4 vibrational state and in an improved determination of the ground-state rotational and centrifugal distortion constants.

Weber, W. H.↗
NASA NTRS1984

A search for formic acid in the upper troposphere - A tentative identification of the 1105-per cm nu-6 band Q branch in high-resolution balloon-borne solar absorption spectra

Infrared solar absorption spectra recorded at 0.02-per cm resolution during a balloon flight from Alamogordo, NM (33 deg N), on March 23, 1981, have been analyzed for the possible presence of absorption by formic acid (HCOOH). An absorption feature at 1105 per cm has been tentatively identified in upper tropospheric spectra as due to the nu-6 band Q branch. A preliminary analysis indicates a concentration of about 0.6 ppbv and 0.4 ppbv near 8 and 10 km, respectively.

Goldman, A.↗
NASA NTRS1985

Tentative identification of the 780/cm nu-4 band Q branch of chlorine nitrate in high-resolution solar absorption spectra of the stratosphere

According to models of the photochemistry of the stratosphere, chlorine nitrate (ClONO2) is an important temporary reservoir of stratospheric chlorine. At night, ClO is believed to combine in a three-body reaction with NO2 to form chlorine nitrate. During daylight, chlorine nitrate is destroyed by photolysis to form free chlorine and NO3. Infrared spectroscopy has the potential to provide a technique for conducting important quantitative measurements of stratospheric chlorine nitrate. The present paper reports a detailed study of spectra in the 780/cm region. This study has led to the tentative identification of the nu-4 band Q branch of ClONO2 as a significant contributor to the observed stratospheric absorption near 780.21 per cm.

Rinsland, C. P.↗
NASA NTRS1985

Measurements of (C-12)H4 nu-4 band halfwidths using a tunable diode laser system and a Fourier transform spectrometer

Air-broadened and N2-broadened halfwidths at room temperature for twenty-five transitions in the nu-4 fundamental band of (C-12)H4 have been determined from IR absorption spectra recorded with a tunable diode laser spectrometer. Two tunable diode lasers operating in the 1250-1380-kayser region were used to obtain these data. Air-broadened halfwidths for twenty of these lines were also determined from additional spectra recorded at 0.01-kayser resolution with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak. The air-broadened halfwidths obtained from these two techniques are very consistent with agreement better than 3 percent in most cases.

Devi, V. M.↗
NASA NTRS1985

Tunable diode laser mesurements of widths of air- and nitrogen-broadened lines in the nu(4) band of C-13H4

Tunable diode laser measurements of air-broadened and N2-broadened halfwidths are reported for 23 lines in the nu(4) band of C-13H4, between 1260 and 1360/cm. For all lines, at least three scans of each of four or more pressures were recorded. The experimental halfwidths presently obtained for C-13H4 are both larger and smaller than the U.S. Air Force Geophysics Laboratory values.

Devi, V. M.↗
NASA NTRS1987

Electron-impact excitation cross sections for the b 3Sigma(+)nu state of H2

Differential and integral cross sections for electron-impact excitation of the b 3Sigma(+)nu state of H2 have been determined in the 20-100-eV impact energy region. The calibration of the cross sections was achieved through the H2 elastic scattering cross sections, which in turn were normalized to absolute He elastic scattering cross sections. Comparison is made with available experimental data and with theoretical results applying Born-Ochkur-Rudge, distorted-wave, and close-coupling approximations.

Khakoo, M. A.↗
NASA NTRS1987

SOR and MGR(nu) experiments on the Crystal multicomputer

This report describes distributed implementations of the red/black SOR algorithm and of the MGR(nu) multigrid algorithm on the Crystal multicomputer. Rates of convergence and observed efficiencies for both algorithms are compared.

Kamowitz, David↗
NASA NTRS1988

Temperature dependence of the hydrogen-broadening coefficient for the nu 9 fundamental of ethane

Experimental results for the temperature dependence of the H2-broadening coefficient for the nu 9 fundamental of ethane are reported. Measurements were made over the temperature range 95-300 K using a novel low-temperature absorption cell. These spectra were recorded with the Doppler-limited diode laser spectrometer at NASA Goddard. The results are compared with recent measurements and model predictions.

Halsey, G. W.↗
NASA NTRS1989

Elemental abundance analyses with coadded DAO spectrograms. VI - The mercury-manganese stars Nu Cancri, Iota Coronae Borealis and HR 8349

The elemental abundances of three mercury-manganese stars, Nu Cancri, Iota Coronae Borealis, and HR 8349, were found to be consistent with previous analyses of this series. As Iota CrB is a double-lined spectroscopic binary with a small velocity amplitude for most of its period, its study required determining whether the observed lines were produced in the primary or secondary or both. The derived abundances and effective termperatures were used along with those of mercury-manganese stars previously analyzed in order to extend the study of probable correlations between abundances, with the effective temperature and surface gravity in accordance with radiative diffusion explanations.

Adelman, Saul J.↗
NASA NTRS1989

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↗
NASA NTRS1990

The nu-process

As the core of a massive star collapses to form a neutron star, the flux of neutrinos in the overlying shells of heavy elements becomes so great that, despite the small cross section, substantial nuclear transmutation is induced. Neutrinos excite heavy elements and even helium to particle unbound levels. The evaporation of a single neutron or proton, and the back reaction of these nucleons on other species present, significantly alters the outcome of traditional nucleosynthesis calculations leading to a new process: nu-nucleosynthesis. Modifications to traditional hydrostatic and explosive varieties of helium, carbon, neon, oxygen, and silicon burning are considered. The results show that a large number of rare isotopes, including many of the odd-Z nuclei from boron through copper, owe much of their present abundance in nature to this process.

Woosley, S. E.↗
NASA NTRS1990

Tunable far-IR laser spectroscopy of jet-cooled carbon clusters - The nu-2 bending vibration of C3

Seven rovibrational transitions of the (01/1/0)-(00/0/0) fundamental bending band of C3 have been measured with high precision with the use of a tunable far-infrared laser spectrometer. The C3 molecules were produced by laser vaporization of a graphite rod and cooled in a supersonic expansion. The astrophysically important nu-2 fundamental frequency is determined to be 63.416529(40)/cm. These measurements provide the basis for studies of C3 in the interstellar medium with far-infrared astronomy.

Schmuttenmaer, C. A.↗
NASA NTRS1991

Measurement of self-broadening of the ozone nu(3) transitions

Self-broadening coefficients have been measured for a number of rovibrational lines in the nu(3) band of ozone, in the frequency range 1015-1058/cm, with J values between 0 and 27, and over a range of K(a) values. A multiparameter nonlinear least-squares fitting procedure is used to reduce the data, and the sensitivity of the procedure to instrument line width, weak satellite features, and absolute intensity has been examined. The retrieved coefficients are compared with millimeter-wave broadening coefficients, direclty measured rotational relaxation times, and recently suggested empirical representations.

Flannery, C.↗