Li(2p ← 2s) + Na(3s) pressure broadening in the far-wing and line-core profiles

This work reports pressure-broadening line-wing and line-core of the lithium Li (2p ← 2s) resonance line perturbed by ground sodium Na (3s) atoms. In far-wing region the calculations are performed quantum-mechanically and are intended to examine the photoabsorption coefficients at diverse temperatures. The results show the existence of three satellites, in the blue wing near the wavelengths 470nm and in the red wing around 862 and 1070nm. For the line-core region, by adopting the simplified Baranger model the line-width and line-shift rates are determined and their variation law with temperature is examined. No published data were found to compare these results with.

Multiple HC3N line observations towards 19 Galactic massive star-forming regions

We performed observations of the HC3N (24–23, 17–16, 11–10, 8–7) lines towards a sample consisting of 19 Galactic massive star-forming regions with the Arizona Radio Observatory 12 m and Caltech Submillimeter Observatory 10.4 m telescopes. HC3N (24–23, 17–16, 11–10, 8–7) lines were detected in sources except for W 44, where only HC3N (17–16, 11–10) were detected. Twelve of the nineteen sources showed probable line wing features. The excitation temperatures were estimated from the line ratio of HC3N (24–23) to HC3N (17–16) for 18 sources and are in the range 23– 57 K. The line widths of higher-J transitions are larger than lower-J ones for most sources. This indicates that the inner dense warm regions have more violent turbulence or other motions (such as rotation) than outer regions in these sources. A possible cutoff tendency was found around LIR ∼ 106 L⊙ in the relation between LIR and full width at half maximum line widths.

Expanding the range of determination of elements on the Grand-AAS atomic absorption spectrometer using several of their absorption lines

One limitation of atomic absorption spectrometry is the narrow range of measurable concentration (1–2 orders of magnitude). In simultaneous multi-element analysis, this may require multiple dilutions of the sample to determine several elements with different concentrations in the sample. Possible ways to expand the range are to linearize the calibration curve by correcting the integral of the absorption signal or to use absorption values on the line wing as an analytical signal and plot several graphs along one line at different distances from its center. Both methods have their drawbacks. We propose another method for expanding the measurable concentration range by using less sensitive absorption lines of elements. A number of elements are identified that have a sufficient number of lines with different sensitivities. The proposed method is compared with the method of linearization of the calibration graph and the calculation of the absorption signal on the line wing. Using as an example Co and Ni, which have sufficiently rich absorption spectra, we have shown the possibility of expanding the measurable concentration range by using several absorption lines: for cobalt, the range is expanded to six orders of magnitude, and for nickel, to five orders of magnitude. Calibration curves are plotted in the concentration ranges 0.24–250.000 μg/L for cobalt and 1.9–250.000 μg/L for nickel. The calibration error is lower than that of the linearization method: 5% against 25 % for cobalt and 4% against 24% for nickel. Thus, the proposed method can be used for simultaneous multielement determination in a wide range of concentrations without diluting the sample.