Rotational level competition in CO sub 2 lasers.
Competition effects between rotational levels of carbon dioxide rotation-vibration band in traveling and standing wave lasers
Mocker, H. W.↗
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The fourth positive system of carbon monoxide observed in absorption at high resolution in the vacuum ultraviolet region.
Fourth positive carbon monoxide system observed in absorption in vacuum UV region, discussing rotational and vibrational band structure
Bass, A. M.↗
Intensity measurements in the B super 3 pi sub 0 plus sub u-X super 1 sigma sub 0 plus sub g system of I sub 2
Rotational lines in iodine B-X system vibrational bands, calculating Doppler, natural and collisional widths
Chutjian, A.↗
A study of the 7667-A band system of Cs2 - The magnetic rotation spectra of the 7667 and 6250-A systems
Diatomic Cs 7667 A band vibrational spectrum analysis
Hessel, M. M.↗
Fluorescence of the gamma, epsilon, and delta systems of nitric oxide - Polarization and use of calculated intensities for spectrometer calibration.
Results of a study in which fluorescence of the gamma system of nitric oxide was obtained by excitation from both the 2144 A line of ionized cadmium and a continuum source. Individual rotational lines of the 2144 A excited fluorescence spectrum were found to be partially polarized and to have polarizations of differ ing sign. Measured relative vibrational band intensities from line and continuum excitation were compared to calculated Franck-Condon factors. Those Franck-Condon factors based on a single potential for the two spin states of the X super pi state agreed better with measured values than those based on separate potentials for the two spin states. Calculated intensities of the v prime = 3 progression were used to calibrate the instrument response in the wavelength region from 2000 to 2500 A and were checked with measured intensities of the v prime = 0.1, and 2 progressions. Fluorescence of the epsilon and delta bands obtained with continuum lamp excitation also were compared to calculated intensities.
Poland, H. M.↗
Auroral spectrum between 1200 and 4000 angstroms.
Results of spectroscopic observations of an auroral event made simultaneously by airborne and satellite-borne scanning spectrometers in the wavelength region between 1200 and 4000 A. Photon emission rates of several vibrational bands of the N2, 2nd positive, Vegard-Kaplan, and Lyman-Birge-Hopfield systems, the N I lines at 1200 and 3466 A, and O I lines at 1304, 1356, and 2972 A were recorded. Model calculations of the emission rates of the observed features are found to be in reasonable agreement with the measurements. Electron impact excites the nitrogen band systems, as well as the O I 1356-A line. A spectral feature at 2150 A is tentatively identified as the (1, 0) gamma band of N O.
Sharp, W. E.↗
Investigation of gas temperature measurements using ultraviolet excitation
A high resolution spectrographic study has been made of the nitrogen first negative system as induced by ultraviolet radiation. The radiation used in this experiment was the neutral helium resonance radiation at 584 A. Nitrogen molecules at approximately 300 K and at a pressure of one torr were ionized by the ultraviolet radiation with the aid of a windowless experimental configuration. The resulting nitrogen fluorescence was analyzed with sufficient resolution to enable study of the intensities of the R branch rotational lines of the 0-0 vibrational band of the first negative system. The data indicate that the induced population of the upper levels approximates a Boltzmann Distribution at the ambient temperature of the gas.
Ofelt, G. S.↗
Scanner observations of selected cool stars
Photoelectric spectral scans at 30-A resolution of 9 dwarfs, 10 giants and 6 supergiants with spectral types GO to M5 were presented. All stars were observed every 4 A from wavelength 3300 to wavelength 7000. Absorption features at this resolution coincide with: strong atomic lines of Fe 1,11, Ca 1,11, Mg 1, and Na 1; vibrational bands of the electronic transitions of TiO, MgH, CaH, SiH, AlH, Cn, Ch, C2, OH, and NH. The dependence of the wavelength 3740 Fe 1 blend and the wavelength 3440 depression on temperature is discussed.
Fay, T. D., Jr.↗
On the ionization potential of molecular oxygen
The ionization potential of O2 was measured by the technique of high resolution photoelectron spectroscopy taking into account the influence of rotational structure on the shape of the vibrational bands. A value of 12.071 + or - .001 eV (1027.1 + or - 0.1 A) was found for the ionization potential. A lowering of the ionization potential caused by a branch-head when delta N = -2 gave an appearance potential for ionization of 12.068 + or - .001 eV (1027.4 + or - 0.1 A).
Samson, J. A. R.↗
Scanner observations of selected cool stars
Photoelectric spectral scans at 30 A resolution of nine dwarfs, ten giants, and six supergiants with spectral types G0 to M5 are presented. (All stars were observed every 4 A from 3300 to 7000 A.) Absorption features observed at this resolution coincide with: strong atomic lines of Fe I, Fe II, Ca I, Ca II, Mg I, and Na I; vibrational bands of the electronic transitions of TiO, MgH, CaH, SiH, AlH, CN, CH, C2, OH, and NH. The dependences of the 3740-A Fe I blend and the 3440-A depression on temperature are discussed.
Fay, T. D., Jr.↗
Experimental differential and integral electron impact cross sections for the B /1-Sigma-u +/ state of H2 in the intermediate-energy region
Utilizing a crossed electron-beam-molecular-beam scattering technique, differential electron impact cross sections (DCS) for the excitation of the nu prime = 2 vibrational band of the B (1-Sigma-u +) state of H2 have been measured and are presented for the first time. These measurements were made at electron impact energies of 15, 20, 30, 40, 50 and 60 eV. At each energy, DCS between scattering angles of 10 and 135 deg were determined. They were then extrapolated to 0 and 180 deg scattering angles to obtain the integral cross sections. These integral cross sections and the Frank-Condon factor for the nu prime = 2 band were used to calculate the total cross sections for the excitation of the B (1-Sigma-u +).
Srivastava, S. K.↗
The HF:HCl ratio in the 14-38 km region of the stratosphere
A balloon-borne high resolution Michelson interferometer recorded near infrared absorption spectra of the 1-0 fundamental vibration bands of HF and HCl in the stratosphere over Australia in March 1977. The ratio of the number density of HF to that of HCl as a function of stratospheric height was deduced from the measurements. Within estimated experimental error, the ratio is constant, its mean value being 0.1.
Farmer, C. B.↗
Lidar temperature profiling: Performance simulations of Masons method
Several methods of using lasers to measure atmospheric temperature profiles were described. Mason's suggestion was analyzed here to assess its capabilities for various lidar configurations. Temperatures were inferred from a measure of the Boltzmann distribution of rotational states in one of the vibrational bands of O2. Differential absorption was measured using three tunable, narrowband pulsed lasers. The outputs of two were tuned to wavelengths at the centers of absorption lines at either end of a particular branch in the band. The third wave-length was in a region of no absorption; its lidar return measured only the atmospheric backscatter, and therefore allowed calculations of the absorption coefficients at the other two wavelengths as a function of altitude. From the ratio of the two line absorption coefficients plus a priori knowledge of the line parameters, the temperature-altitude profile were calculated.
Schwemmer, G. K.↗
Lidar temperature profiling - Performance simulations of Mason's method
In Mason's method (1975) atmospheric temperatures are inferred from a measure of the Boltzmann distribution of rotational states in one of the vibrational bands of O2. Differential absorption is measured using three tunable, narrowband pulse lasers. The outputs of two are tuned to wavelengths at the centers of absorption lines at either end of a particular branch in the band; the third wavelength is in a region of no absorption. The temperature-altitude profile can be calculated from the ratio of the two line absorption coefficients plus a priori knowledge of the line parameters. In the present paper, computer simulations of various lidar configurations are made, using different line pairs in the atmospheric bands of O2 (approximately 630, 690, and 760 nm). Simulated results are presented for temperature profiles measured from a Space Shuttle lidar.
Schwemmer, G. K.↗
A direct nuclear-pumped He-3-CO laser
Direct nuclear pumping of a low-temperature (150 K) He-3-CO laser has been achieved using the volumetric He-3(n,p)H-3 nuclear reaction. Lasing occurred on the vibrational bands of CO at about 5 microns. Effects of N2 on the system were investigated, as well as scaling of laser output with CO concentration, thermal neutron flux, and total pressure. This is the first volume-pumped, nuclear powered CO laser.
Jalufka, N. W.↗
Vibration-rotation intensities of SiO
Dipole moment matrix elements have been computed for a large number of transitions of astrophysical interest for the more abundant isotopes of SiO. The wave functions utilized were obtained from a direct solution of the Schroedinger equation with an accurate RKR potential. The dipole moment function, in the form of a Pade approximant, was chosen to reproduce the experimental measurements near equilibrium, to have the proper united and separated atom limits, and to have the correct long-range asymptotic dependence on internuclear separation. Because of the large number of transitions involved, and to facilitate applications, the squares of the dipole moment matrix elements were fitted by a least-squares procedure to polynomials in v and J. In addition, Einstein A coefficients are given for observed maser transitions and for selected vibrational bands. These latter are compared with previous calculations, and it is concluded that for the higher Delta v transitions, the present results represent a significant improvement.
Tipping, R. H.↗
Radiative lifetimes and quenching rate coefficients for directly excited rotational levels of OH/A 2Sigma +, v-prime = 0/
A narrow-bandwidth pulsed dye laser was used to excite OH X 2Pi i radicals to the A 2Sigma(+) state by pumping in the (0, 0) vibrational band around 308 nm. The radiative lifetimes of specific (K-prime, J-prime) rotational levels in v-prime = 0 were measured at low pressures (not greater than 1 mtorr), which yielded a mean lifetime of 0.71 + or - 0.009 microsec (2 sigma). Electronic quenching rate constants for N2, O2, H2O, and H2 were measured for a range of initially excited rotational levels. A strong dependence of this rate constant on the initially excited rotational level was found for N2, and less markedly for O2, with the rate constant tending to increase for the lowest rotational levels K-prime not greater than 3. The implications of these results for the laser-induced fluorescence detection of atmospheric OH are discussed.
Mcdermid, I. S.↗
Radiative lifetimes and dipole moments of the A 2Sigma/+/, B 2Sigma /+/, and C 2Sigma/+/ states of OH
After describing independent theoretical studies of the eigenfunctions of the X 2Pi and excited A 2Sigma(+), B 2Sigma(+), and C 2Sigma(+) states of OH, results are presented for the transition dipole moments connecting each excited state to the others and to the ground state. The radiative lifetimes derived from calculation of the bound-bound and bound-free vibrational band transition probabilities are compared with measured values, confirming recent measurements of the A 2Sigma(+) and C 2Sigma(+) states but not the lifetimes measured for the B 2Sigma(+) state.
Langhoff, S. R.↗