Measurements Of Spectral Lines Research Articles

Measurements of relative transition probabilities of ns-4p, nd-4p, and nf-3d transitions in neutral potassium

Relative transition probability ( A-value) measurements are reported for the ns-4 p ( n = 6–15), nd-4 p ( n = 5–13), and nf-3 d ( n = 7–14) series transitions in neutral potassium (KI). The results are based on intensity measurements of optically-thin KI spectral lines from a steady-state potassium emission source. The source employed was a radially-symmetric potassium-seeded argon plasmajet containing ≲ 5 mole per cent K-atoms. Local emission coefficients were obtained by means of the Abel transform. For the prevailing free-stream conditions ( P ∼ 11 torr, T ∼ 3200 K, n e ∼ 10 14 cm -3), the potassium excited state populations are described by a Boltzmann distribution down to and including the ground state. The reported A-values are normalized to that of the 580.2 nm line (7 s-4 p 3 2 transition). The relative accuracy is estimated to be 5–20% for the ns-4 p series and 15–25% for the nf-3 d transitions. With the exception of the data for the 6 s-4 p and all nf-3 d transitions, the measurements agree to within estimated experimental uncertainties with the values given in the NBS tabulation [Wiese et al. (1969)], although systematic differences are observed. For the exceptions noted, the measurements lie 25–50% below the relative NBS values. Comparison is also made to recent calculations of Lindgard and Nielson, and Ormonde.

Spectroscopic investigation of the two-nucleus galaxy Markaryan 266

Kinematic and dynamical studies of the two-nucleus galaxy Markarian 266 are presented. Measurements of the spectral lines show that the nuclei rotate in opposite directions with velocities of 132 km/s (nucleus a) and 286 km/s (nucleus b). The difference between the radial velocities of the nuclei is about 280 km/s and the masses of the nuclei are 7-billion solar masses (nucleus a) and 10-billion solar masses (nucleus b). Under the assumption that this galaxy was formed by the decay of a single body, two possible developments after the decay are considered: (1) the nuclei revolve about a common center of gravity, and (2) they fly apart in opposite directions. The orbital mass and angular momentum of the system are calculated for the former case, while the angular momentum, decay energy, and age of the system are calculated for the latter cases.

The coronal and transition region temperature structure of a solar active region

Using measurements of EUV and X-ray spectral lines we derive the differential emission measure vs electron temperature T from the transition region to the corona of an active region (105 T 106 K (i.e. that mainly responsible for the X-ray emission) is about 75% of the total. We also examine the use of Mg x λ 625 A as an indicator of coronal electron density. A set of theoretical energy balance models of coronal loops in which the loop divergence is a variable parameter is presented and compared with the observations. Particular attention is given to the limitations inherent in any such comparison.

ChemInform Abstract: DIODE LASER MEASUREMENTS OF AMMONIA ν2‐BAND SPECTRAL LINES

Chemischer InformationsdienstVolume 10, Issue 40 Physical Inorganic Chemistry ChemInform Abstract: DIODE LASER MEASUREMENTS OF AMMONIA ν2-BAND SPECTRAL LINES F. CAPPELLANI, F. CAPPELLANISearch for more papers by this authorG. RESTELLI, G. RESTELLISearch for more papers by this author F. CAPPELLANI, F. CAPPELLANISearch for more papers by this authorG. RESTELLI, G. RESTELLISearch for more papers by this author First published: October 2, 1979 https://doi.org/10.1002/chin.197940004Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume10, Issue40October 2, 1979 RelatedInformation

Nonadiabatic long-range forces

The dependence of the long-range interactions between a Rydberg electron and an ionic core on the nuclear charge of the core is analyzed. It is pointed out that the nonadiabatic interaction will be most readily apparent in spectral-line measurements of systems belonging to the beryllium and boron isoelectronic sequences. A quantitative analysis is presented of data for Cl xiv.

NH 3 spectral line measurements on Earth and Jupiter using a 10 μm superheterodyne receiver

Measurements of absolute line positions and shapes of eleven absorption lines of NH 3 were made using an infrared heterodyne spectrometer. Line profiles were obtained with 5 MHz resolution. NH 3 line positions relative to 12C 16O 2 and 13C 16O 2 local oscillator laser line emission frequencies were determined to ±3 MHz. Using the obtained data a search list for NH 3 spectral lines on Jupiter was generated. Observations of Jovian polar regions in search of NH 3 aR(1,1) and sQ(2,1) auroral emission revealed possible strong nonthermal features. The line widths were consistent with low local kinetic temperatures. The relatively high line intensities, determined by local pumping mechanisms, corresponded to temperatures of several hundred Kelvins. Experimental details and implications of these measurements are discussed.

Astronomy and Spectroscopy

Spectroscopy is vital to present day studies in astronomy. The detection, measurement and interpretation of spectral lines or features in electromagnetic radiation provide one of the greatest sources of astronomical information.

光学的繰返し走査とミニコンを用いた発光分光分析のＳＮ比向上

A quartz plate (20×10×2mm), made to vibrate at ca. 100 Hz, was mounted behind the entrance slit of a monochromator to scan a narrow wavelength region (max.: 0.33 nm) repetitively. Spectral signals synchronized with the scan were accumulated on a minicomputer for the pre-determined number of times. The rate of accumulation was about 12000 per min., After the data acquisition, the spectrum was displayed on a strip chart recorder. The method was applied to the detection of metals at low ppb levels in solutions with a low-wattage microwave torch discharge. With a 2-min. accumulation, detection limits were lowered by an order of magnitude as compared with the results measured with a lock-in amplifier. The system was also applicable to the simultaneous measurement of adjacent spectral lines lying as near as 0.05 nm.

Transport of uranium free particles in a d.c. arc plasma burning in air at atmospheric pressure

The transport parameter ψ was calculated for the free particles of uranium in a d.c. arc plasma burning in air. Using the “wire method” the volatilization rate ( Q w), the total concentration of free particles ( n t), the axial velocity ( v j) of uranium particles and the plasma cross section ( S) were measured. The transport parameter was calculated for cylindrical symmetry of the arc. The total particle concentration calculated by the wire method was compared to values obtained by absolute intensity measurements of ion and atom spectral lines of uranium. This led to an estimate of the molecular concentration of uranium in the d.c. arc plasma.

Advantages and Limitations of Quantitative Spectral Classification

The measurements of spectral lines of moderate dispersion slit spectrograms for F, G and K type stars give a large quantity of information. The measurements are time-consuming in comparison with visual classification, but the use of digitized microphotometers reduces the task, and the method is now promising. The interpretation of the measurements raises some problems, which are briefly discussed.

Small “Non-velocity” Redshifts in Galaxies

THE question of whether or not the small excess redshifts observed in some companion galaxies1,2 have a non-velocity origin has recently been raised. The de Vaucouleurs3 have pointed out that small, systematic errors in the redshifts of E and SO galaxies might arise because the lines in the low dispersion spectra on which they are measured do not have well-determined effective wavelengths. The data reported here support this possibility. In the three cases I present, systematic differences arise between velocities derived from measurements of CA II, H(λ3968.5) and K(λ3933.7) carried out “classically” (with a visually positioned, two coordinate measuring engine) and velocities derived from either “classical” measurements of other spectral lines in the same object or measurements of the same H and K lines using numerical techniques.

Method for Measuring Doppler Shifts in Arc-Heated Flows

A novel method of determining both the Doppler and Stark shifts in a single measurement of spectral lines emitted by the arc-heated flow from a plasma jet has been successfully demonstrated. The method uses a spherical mirror arranged with its optical axis coincident with the optical axis of a Fabry-Perot interferometer and with its center of curvature at the center line of the flow. The common optical axis lies at an angle to the flow. With this system, both red-and blue-shifted line profiles are recorded in the same spectral scan. If conditions are such that the red-and blue-shifted profiles are not resolvable, the blue-shifted component is chopped so that the recorded signal consists of the envelopes of both the red-shifted profile and the superimposed red-and blue-shifted profiles. The wavelength difference between the blue-and red-shifted line profiles is exactly twice the Doppler shift integrated along a line of sight through the flow and is independent of a Stark shift. The Stark shift is given by the wavelength difference between the absolute line center and the midpoint of the red-and blue-shifted lines. Abel inversion of integrated line shift data has yielded radial velocity profiles to an accuracy of +/-3% in a supersonic, arc-heated argon flow.

Transition probabilities of some ArI and ArII spectral lines

The transition probabilities of four lines of singly ionized argon have been determined from radiance measurements of spectral lines emitted by an argon-arc discharge in a sealed tube. The wavelengths of the lines are λ = 4348, 4806, 4847, and 4879 Å. Self-absorption was taken into account. Within the experimental errors, our results agree with the values calculated theoretically by Statz et al. The transition probabilities of four spectral lines of neutral argon have been found to be in agreement with literature values. The lines in question are located at 3834, 4251, 4259, and at 6965 Å. The temperature on the axis of the discharge was obtained from the spectral density of the radiance in the continuous spectrum emitted by the discharge and, in one experiment, also from the radiances of three spectral lines of neutral argon. In the latter case, use was made of the transition probability of the line λ = 4300 Å and of the ratio of the transition probabilities of the lines λ = 3834 and 6965 Å. These data were taken from the literature; the results agree with those obtained from the continuous spectrum.

Experimental Verification of the Relativistic Doppler Effect

An experiment has been performed to measure the quadratic Doppler shift, ∼(1−υ2/c2)−12, predicted by the special theory of relativity. A moving beam of radiating hydrogen atoms with velocities ranging up to 2.8 × 108 cm/sec has been viewed from the incoming and outgoing directions simultaneously. Averaging wavelength measurements of a particular spectral line for the two observations gives a measurement of the quadratic shift. The number (12) in the theoretically predicted exponent can be compared to the experimental results. The latter gives the value of this exponent to be 0.498 ± 0.025. The predominant factor leading to the experimental uncertainty is the width of the spectral lines involved in the measurement.

Optical investigation of an atomic hydrogen flame

A flame of atomic hydrogen has been investigated for the purpose of testing its possibilities regarding the investigation of thermic emission and absorption of radiation by gases (§ 1). The apparatus (§ 2) is sketched in fig. 1. The optical arrangement for the measurement of temperatures by means of line reversal is given in fig. 2 and described in § 3. The general appearance and the flame properties are described in § 4, where amongst other things it is pointed out that the discharge is periodic. The distribution of the temperature in a horizontal section of the flame (§ 5) is represented in fig. 3, while fig. 4 and the table give the vertical course of the temperature as well as its dependance on the arc current etc. Simultaneous reversal measurement of several spectral lines was found to lead to the same reversal temperatures (§ 7), the conclusion being that the population of the respective upper levels complies with the Boltzmann formula. From the combined results we may conclude that the flame of atomic hydrogen can be used with advantage for the determination of transition probabilities of spectral lines with excitation energy ≤ 6 eV. For a number of details, see the original publication 1).

Optical Methods for Reducing the Effects of Photographic Plate Graininess With Special Reference to Spectral Line and Star Image Measurements

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text F. E. Wright, "Optical Methods for Reducing the Effects of Photographic Plate Graininess. With Special Reference to Spectral Line and Star Image Measurements," J. Opt. Soc. Am. 21, 485-496 (1931) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Intensity Measurements of Spectral Lines

Intensity Measurements of Spectral Lines