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20212025
most citedTemperature and density dependence of line profiles of sodium perturbed by helium

13 citations · 23 across the 6 of their papers we have counts for

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astro-ph.SR2024

New theoretical study of potassium perturbed by He and a comparison to laboratory spectra

N. F. Allard, J. F. Kielkopf, K. Myneni +1

We report on our new calculations of unified line profiles of K perturbed by He using ab initio potential data for the conditions prevailing in cool substellar brown dwarfs and hot…

astro-ph.SR2023★ 13 cited

Temperature and density dependence of line profiles of sodium perturbed by helium

N. F. Allard, K. Myneni, J. N. Blakely +1

Ultracool stellar atmospheres show absorption by alkali resonance lines severely broadened by collisions with neutral perturbers. In the coolest and densest atmospheres, such as th…

astro-ph.SR2022★ 4 cited

Collision-induced satellite in the blue wing of the Balmer-beta line and consequences on the Balmer series

F. Spiegelman, N. F. Allard, J. F. Kielkopf

In this paper we emphasize the non-Lorentzian behavior of the Balmer series in helium-dominated DBA white dwarf stars for which the decades-old problem exists for the determination…

astro-ph.SR2022★ 3 cited

Collisional effects in the blue wing of the Balmer-alpha line

N. F. Allard, F. Spiegelman, J. F. Kielkopf +1

In order to investigate the near wing of the Lyman-alpha line, accurate line profile calculations and molecular data are both required due to the existence of a close line satellit…

astro-ph.SR2021★ 3 cited

Collisional effects in the blue wing of Lyman-alpha

F. Spiegelman, N. F. Allard, J. F. Kielkopf

Spectral observations below Lyman-alpha are now obtained with the Cosmic Origin Spectrograph (COS) on the Hubble Space Telescope (HST). It is therefore necessary to provide an accu…