Wavelengths Of Absorption Lines Research Articles

Reference wavelengths of Si ii, C ii, Fe i, and Ni ii for quasar absorption spectroscopy.

Wavelengths of absorption lines in the spectra of galaxies along the line of sight to distant quasars can be used to probe the variablility of the fine structure constant, α, at high redshifts, provided that the laboratory wavelengths are known to better than 6 parts in 108, corresponding to a radial velocity of ≈20 ms-1. For several lines of Si ii, C ii, Fe i, and Ni ii, previously published wavelengths are inadequate for this purpose. Improved wavelengths for these lines were derived by re-analysing archival Fourier transform (FT) spectra of iron hollow cathode lamps (HCL), a silicon carbide Penning discharge lamp, and with new spectra of nickel HCLs. By reoptimizing the energy levels of Fe i, the absolute uncertainty of 13 resonance lines has been reduced by over a factor of 2. A similar analysis for Si ii gives improved values for 45 lines with wavelength uncertainties over an order of magnitude scer than previous measurements. Improved wavelengths for eight lines of Ni ii were measured and Ritz wavelengths from optimized energy levels determined for an additional three lines at shorter wavelengths. Three lines of C ii near 135 nm were observed using FT spectroscopy and the wavelengths confirm previous measurements.

The rare earth elements as candidates for isotope selective graphite furnace applications

The applicability of isotope selective diode laser graphite furnace atomic absorption spectrometry to the rare earth elements is discussed. Useful transitions exist for the elements Sm, Eu, Gd, Er and Lu. Doppler-limited and Doppler-free experimental spectra are presented. Values of the characteristic masses and the limits of detection are given for the following isotopes and wavelengths of absorption lines, respectively: 154Sm at 672.6 nm, 151Eu and 153Eu at 686.5 nm, 170Er at 658.4 nm and at 841.0 nm. For these lines also the coefficients of collisional broadening by argon are determined.

Wave Lengths of Absorption Lines in the Spectra of Beta Canis Majoris Stars.

Wave Lengths of Absorption Lines in the Spectra of Beta Canis Majoris Stars.

Wave Lengths of Absorption Lines in the Spectrum of Omicron Ceti.

view Abstract Citations (8) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Wave Lengths of Absorption Lines in the Spectrum of Omicron Ceti. Merrill, Paul W. Abstract A list of 1347 absorption lines, mostly atomic, between N 3528 and N 4462 in the spectrum of the longperiod variable o Ceti, spectrum M6e, has been derived from measurements of five spectrograms with dispersions of from 2.3 to 4.5 A/mm. The measured displacements of various lines increase with the atomic excitation potentials of the lower levels of the lines by 1.3 km/sec per electron volt. The probable cause is an upper expanding shell of gas cooler than that of the reversing layer. Iron lines appear to have small negative residuals compared to lines of other metals. Publication: The Astrophysical Journal Pub Date: July 1959 DOI: 10.1086/146702 Bibcode: 1959ApJ...130..123M full text sources ADS | data products SIMBAD (3)

Displacements of Lines in the Spectra of Long-Period Variables.

view Abstract Citations (18) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Displacements of Lines in the Spectra of Long-Period Variables. Merrill, P. W. Abstract Wave lengths of absorption lines in Me spectra suitable for velocity measurements with moderate dispersion are listed in Table i. Data concerning periodic variations in the displacements of the dark lines, although meager, indicate that, within two months of maximum light, changes in velocity do not exceed a very few kilometers per second. The mean measured displacements of the dark lines are assumed to represent the true stellar velocities. The emission lines, as is well known, are regularly shifted o.i or 0.2 A toward the violet with respect to the absorption spectrum. These shifts, measured in 72 stars (Table 3), are plotted against spectral type in Figure i and against period in Figure 2. The relationship with period furnishes the best method of correcting the radial velocities determined from bright lines alone Publication: The Astrophysical Journal Pub Date: May 1941 DOI: 10.1086/144274 Bibcode: 1941ApJ....93..380M full text sources ADS | Related Materials (1) Reprint: 1941CMWCI.644....1M