Absolute Line Intensities Research Articles

Absolute intensity measurements at different temperatures of the C 12O 216 bands 30°1 I←00 00 and 30°1 IV←00 00

The absolute intensities of the vibration-rotation lines of the transitions 30 01 I←00 00 and 30 01 IV←00 00 of CO 2 have been determined from spectra obtained with a Fourier-Transform interferometer and at different temperatures (197°, 233° and 294°K) with a resolution of 0.075 cm -1. Also, the rotationless transition moments ¦ R¦, the vibration-rotation interaction factors F( m) and the total band intensities were computed using the measured vibration-rotation line intensities. The values obtained are ▪

High resolution spectral measurement of the HNO_3 113-μm band using tunable diode lasers

High resolution spectra in the region of the 2nu(9) band of nitric acid have been obtained for selected portions of the HNO(3) spectrum using tunable diode laser techniques. Continuous spectra are presented from 891.25 cm(-1) to 898.77 cm(-1), with a spectral resolution </=0.001 cm(-1) (30 MHz). Absolute line intensities and line positions are presented. Absolute wavelength calibration was obtained by frequency mixing the diode laser with a C(13)O(2)(16) isotope laser. Self and foreign gas (N(2)) broadening coefficients were iteratively calculated from the experimental data and were determined to be alpha(a) = 0.8 cm(-1)/atm and alpha(f) = 0.13 cm(-1)/atm, respectively.

New Absolute Intensities of the Emission Lines of 15 Planetary Nebulae the Members of the Galactic Centre Group

The new results have been obtained for 15 planetary nebulae, using the new spectrograms obtained at the Abastumany Observatory in 1971. The planetaries belong to the large Galactic centre group, studied by the authors earlier.

The absorption spectrum of CO 2 around 7740 cm -1

Absolute intensities of the vibration-rotation lines of the CO 2 401 II←000 band 7734 cm -1 are measured under high-resolution, low-pressure conditions by use of a White-type 25-m base-path, absorption cell together with a 5-m Czerny-Turner spectrometer. The total band intensity S B , the purely vibrational transition moment ▪, and the vibration-rotation interaction constant ζ are calculated from the intensity measurements. The values obtained for these parameters are S B (401 II) = (7.06±0.07) × 10 -5 cm -2 atm -1 293°K, ▪ = (3.08±0.03)×10 -5 debye, and ζ = (2.5±0.5)×10 -4. The intensity of the associated “hot band” 411 II←010 is also determined and found to be S B (411 II←010) = (0.53±0.02)×10 -5 cm -2 atm -1 293°K.

Emission measures and structure of the transition region of a sunspot from emission lines in the far ultraviolet

Absolute intensities of emission lines in the wavelength range from 1200 A to 1817 A from the large sunspot in McMath region 12510 near Sun center are presented. The intensities are averaged across the umbra and penumbra of the sunspot. The observations were made with the NRL slit spectrograph on Skylab. Emission measures are derived from the measured intensities. Assuming a balance between the divergence of the conductive energy flux and the radiative energy losses, a self-consistent model of the lower transition region in the sunspot is constructed. The model gives a constant pressure of about 0.19 dyne cm-2, and a conductive flux which decreases approximately one order of magnitude between 2 × 105 K and 4 × 104 K. The temperature gradient is relatively constant, increasing slowly with decreasing temperature.

Ladungsaustausch zwischen Arll/Xell und Mg / Charge Exchange between Arll/Xell and Mg

In an Argon-Magnesium-Plasma and a Xenon-Magnesium-Plasma number densities of the four lowest excited levels in Magnesium II were measured using a special absorption method and the absolute spectral line intensities from an optically non-thin layer. Near-Resonant-Charge-Exchange is demonstrated experimentally between Argon ions and MgII(4s2S) and between Xenon ions and Mgll (3p2Po), respectively

The behaviour of a 10.6 mu m pulsed spin-flip Raman laser as a spectroscopic source

Spectra of ammonia (NH3) gas at about 870 cm-1 have been obtained using a pulsed InSb spin-flip Raman laser. Changes in the temperature of the InSb crystal were found to produce large changes in the absolute and relative intensities of the absorption lines. The observed line intensities were also found to be dependent on the pump power applied to the InSb crystal. These effects are attributed to mode-pulling and mode-hopping in the InSb crystal and to the presence of more than one axial mode. There is also some evidence for the presence of higher-order transverse modes.

ChemInform Abstract: QUANTITATIVE CHEMICALLY INDUCED DYNAMIC NUCLEAR POLARIZATION (CIDNP) STUDY OF THE PHOTOLYSIS OF BENZALDEHYDE IN SOLUTION

Qualitative studies of the polarizations in the CIDNP spectra observed from benzaldehyde in a series of solvents are reported and the reaction mechanism which leads to polarized products in hexane solution is established. The time-evolution of two signals which results from isolated protons in single products has been observed in hexane solution under conditions of low overall conversion to products. The results have been analysed using a kinetic model of the reaction and the diffusion description of CIDNP. The quantitative results are entirely consistent with the model, and values of the diffusional correlation time τc= 2.6 ± 0.3 × 10–12 s and the rate constant for hydrogen transfer between the ketyl radical and ground-state benzaldehyde, k3= 1 × 106 mol–1 dm3 s–1, are reported. A feature of the theoretical treatment is the use of intensity ratios to overcome problems of absolute intensities of lines observed in the products of radical reactions.

Measurement of the intensity of the 2–10 Å radiation emitted by laser plasmas generated from targets with nuclear chargesZ= 12–23 and determination of the plasma electron temperature

Measurements were made of the temperature of laser plasmas formed by irradiation (with a flux of ~5×1014 W/cm2 density) of targets containing deuterium and heavy-element impurities and of homogeneous targets with the nuclear charge in the range Z = 12–23. The temperature was deduced from the relative intensities of dielectronic satellites and resonance lines of heliumlike/and hydrogenlike ions. The dimensions of various regions of a laser plasma jet, characterized by temperatures in the range 200–800 eV, were estimated. The absolute intensities of the spectral lines in the 2–10 A range indicated that the plasma radiation power ranged from 104 to 108 W.

Absolute emission line intensities for V1016 Cyg.

view Abstract Citations (20) References (37) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Absolute emission-line intensities for V1016 Cygni. Ahern, F. J. Abstract Photometric and spectrophotometric observations have been made of 1 016 Cygni to determine the absolute intensities of the brighter emission lines. The Balmer decrement is much less steep than it was when measured in 1966 by O'Dell. Since the total brightness of the nebula has not increased since 1966, this cannot be interpreted as a decrease in reddening. We postulate an additional source of Ha emission which has since disappeared. The forbidden-line intensity ratios indicate a 1973 density of log Ne = 6.86 i 0.04, and temperature of Te = 11,900 i 500 K. The change in the intensity ratio [0 ii'] A43631[O ii'] A5007 and [0 iii] A4959/Hfl indicates that the density has not decreased by more than a factor of 1.6 between 1966 and 1973. A stratification model is presented for the case of a sphere of uniform density and temperature, and the relative intensities of He ii A4686/H imply a blackbody effective temperature of T* = 164,000 i 3600 K for the central star. If the Balmer line optical depth arises from hydrogen in the 2s state, we infer a radius of 1.0 >c 1016 cm and a mass of 0.027 M0.. Photometric observations relative to NGC 7027 indicate an Hfl flux of 3.69 + 0.20 x 10-li ergs s . Subject headings: planetary nebulae - stars, individual - stellar evolution Publication: The Astrophysical Journal Pub Date: May 1975 DOI: 10.1086/153554 Bibcode: 1975ApJ...197..639A full text sources ADS | data products SIMBAD (1)

Quantitative chemically induced dynamic nuclear polarization (CIDNP) study of the photolysis of benzaldehyde in solution

Qualitative studies of the polarizations in the CIDNP spectra observed from benzaldehyde in a series of solvents are reported and the reaction mechanism which leads to polarized products in hexane solution is established. The time-evolution of two signals which results from isolated protons in single products has been observed in hexane solution under conditions of low overall conversion to products. The results have been analysed using a kinetic model of the reaction and the diffusion description of CIDNP. The quantitative results are entirely consistent with the model, and values of the diffusional correlation time τc= 2.6 ± 0.3 × 10–12 s and the rate constant for hydrogen transfer between the ketyl radical and ground-state benzaldehyde, k3= 1 × 106 mol–1 dm3 s–1, are reported. A feature of the theoretical treatment is the use of intensity ratios to overcome problems of absolute intensities of lines observed in the products of radical reactions.

The cyanogen bands of Comet Bennett 1970 II

The CN band spectrum of Comet Bennett 1970 II was photographed on April 14, 1970. In addition to the (0,0) band, some other faint lines were observed, which arise either from the (1,1) band of the normal isotopic species or from the (0,0) band of 13CN. The Swings effect was investigated theoretically and found to give good agreement with observation. An estimate is made of the pure rotational transition rate in the ground state of CN. Absolute intensities of the CN lines were found by comparison with the lunar spectrum. From these measurements the distribution, density and total mass of cyanogen in the gaseous coma of the comet are estimated.

Line-intensities in the photosphere-chromosphere transition region

We present results from eclipse spectra in the wavelength region 4588–4682 A, taken during the eclipse of February 15, 1961 at Brac, Yugoslavia. Absolute line intensities have been determined in the photosphere-chromosphere transition region. The method of reduction is discussed in Section 2 and the observed variation of the total intensity as a function of the height is shown for a number of lines in Figures 5–8. The results for the Fe i lines are compared with computations (as described in Paper I: van Dessel, 1970) for various solar model atmospheres (Section 4). The model, which combines Holweger's (1967) temperature distribution for the excitation temperature with the HSRA model (Gingerich et al., 1971) for the electron temperature, yields a better agreement than all pure LTE-models.

Absolute and relative line intensity measurements when the spectral lines are not optically thin

The curves of growth were used in order to determine the Doppler absorption coefficient at the line center, k D0 , from absolutely measured line intensities (equivalent widths) and theoretical widths. It is shown that the relative line intensities from a single path and a double path may be used for the determination of absorption coefficients and absolute oscillator strengths, for estimating absorption at the inhomogeneous ends of a plasma column, and for assessing the approach to thermal equilibrium. Measurements were carried out on the red argon lines arising from the 4 s–4 p transition arrays. The influence of plasma diagnostics on the f-value is considered, and our f-values are compared with other measurements.

Effect of emission intensity fluctuations on the accuracy of temperature measurements on a plasma stream by means of absolute line intensities

Effect of emission intensity fluctuations on the accuracy of temperature measurements on a plasma stream by means of absolute line intensities

The Forbidden Rotational Spectrum of GeH4 in the Ground Vibronic State

The pure rotational spectrum of the tetrahedral molecule GeH4 has been studied with a 10.6 m light-pipe absorption cell and a conventional Michelson interferometer. Fifteen lines have been observed between 50 and 130 cm−1 with a theoretical resolution of 0.5 cm−1. These lines have been identified as arising from forbidden (J → J + 1) transitions for the rotational levels J = 9–23. A detailed discussion is presented of the identification of the absorption mechanism with the distortion electric dipole moment μD produced in the ground vibronic state by centrifugal effects. Particular attention is paid to showing that the rotational transitions within the vibrational state v4 do not contribute to the observed spectrum. The theoretical problem of determining the rotational constant B0 and the scalar distortion constant DS from the data is considered. It is shown that the frequency shifts due to the fourth-rank tensor distortion interaction must be taken into account in the analysis. It has been determined that B0 = (2.696 ± 0.003) cm−1 and DS = (3.3 ± 0.6) × 10−5 cm−1. From estimates of absolute line intensities, it has been found that [Formula: see text].

Anwendung der Weitwinkelinterferenzen zur Untersuchung von akusto-elektrischen Gitterschwingungen in Kadmiumsulfid / Application of the Pseudo-Kossel-Line-Technique for the Investigation of Acoustoelectric Lattice Jibrations in Cadmium Sulfide

Changes in absolute and relative intensities of Pseudo-Kossel lines from crystals containing lattice vibrations were observed. Since the relation between vibration amplitude and intensity modification is known theoretically, vector amplitudes and gain factors of the acoustoelectric amplification can be determined. Advantages of this method are discussed.

Theory of Absolute Intensities for Vibration-Rotation Transitions in Methane

Transition dipole moments have been calculated for lines in the ${\ensuremath{\nu}}_{3}$, ${\ensuremath{\nu}}_{4}$, $2{\ensuremath{\nu}}_{3}$, and $3{\ensuremath{\nu}}_{3}$ vibration-rotation bands of $^{12}\mathrm{C}$${\mathrm{H}}_{4}$. The values of ${\ensuremath{\mu}}^{2}$ are 0.76 \ifmmode\pm\else\textpm\fi{} 0.10, 0.69 \ifmmode\pm\else\textpm\fi{} 0.04, (1.86 \ifmmode\pm\else\textpm\fi{} 0.07) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}3}$, and (2.96 \ifmmode\pm\else\textpm\fi{} 0.16) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}6}$ ${\mathrm{D}}^{2}$, respectively. These results have been applied to predict absolute line intensities. In particular, for the $P7F$ line at 2947.912 ${\mathrm{cm}}^{\ensuremath{-}1}$, the calculated intensity is (1.34 \ifmmode\pm\else\textpm\fi{} 0.17) ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{atm}}^{\ensuremath{-}1}$ at 300\ifmmode^\circ\else\textdegree\fi{} K. Furthermore, ultraweak absorption features observed in the $3{\ensuremath{\nu}}_{3}$ region may be accounted for on the basis of transitions with $J\ensuremath{\approx}30$.

Absolute beam-foil excitation probabilities of hydrogen-like states in iron

By measuring the absolute intensities of hydrogen-like spectral lines, we have deduced absolute foil-excitation probabilities for several levels of high principal quantum number ( n) and several emerging charge states of a 1.5-MeV iron beam. Core polarization allows the partial resolution of transitions involving different l-values for the same initial and final n. The probability that an iron ion emerging from the foil with charge state g is in a state characterized by n is found to be of order 10 −3 for n = 6–9 and q = 4 +−7 +. For a given n, population of high l appears to be favored. A discussion of the overall state population distribution among high n states following foil excitation will be presented.

Measurement of temperature by recording the absolute line intensity with apparent increase of plasma optical thickness

Measurement of temperature by recording the absolute line intensity with apparent increase of plasma optical thickness