J/A+A/566/L8 He IR absorption profiles (Kowalski, 2014)
Infrared absorption of dense helium and its importance in the atmospheres of
cool white dwarfs.
Kowalski P.M.
<Astron. Astrophys. 566, L8 (2014)>
=2014A&A...566L...8K 2014A&A...566L...8K
ADC_Keywords: Atomic physics
Keywords: atomic processes - dense matter - stars: atmospheres - white dwarfs
Abstract:
Hydrogen-deficient white dwarfs are characterized by very dense,
fluid-like atmospheres of complex physics and chemistry that are still
poorly understood. The incomplete description of these atmospheres by
the models results in serious problems with the description of spectra
of these stars and subsequent difficulties in derivation of their
surface parameters. Here, we address the problem of infrared (IR)
opacities in the atmospheres of cool white dwarfs by direct ab initio
simulations of IR absorption of dense helium.
We applied state-of-the-art density functional theory-based quantum
molecular dynamics simulations to obtain the time evolution of the
induced dipole moment. The IR absorption coefficients were obtained by
the Fourier transform of the dipole moment time autocorrelation
function.
Description:
The data table contains the helium IR absorption profiles. The first
column is the frequency in cm-1. The columns 2 to 11 provide the
absorption profiles (absorbance/density3) in cm-1*amagat-3.
derived for different temperatures.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
opacity.dat 135 400 Helium IR absorption profiles
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Byte-by-byte Description of file: opacity.dat
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Bytes Format Units Label Explanations
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1- 5 I5 cm-1 Freq [50/20000] Frequency
7- 18 E12.7 --- Abs1 Absorption coefficient at T=1000K (1)
20- 31 E12.7 --- Abs2 Absorption coefficient at T=2000K (1)
33- 44 E12.7 --- Abs3 Absorption coefficient at T=3000K (1)
46- 57 E12.7 --- Abs4 Absorption coefficient at T=4000K (1)
59- 70 E12.7 --- Abs5 Absorption coefficient at T=5000K (1)
72- 83 E12.7 --- Abs6 Absorption coefficient at T=6000K (1)
85- 96 E12.7 --- Abs7 Absorption coefficient at T=7000K (1)
98-109 E12.7 --- Abs8 Absorption coefficient at T=8000K (1)
111-122 E12.7 --- Abs9 Absorption coefficient at T=9000K (1)
124-135 E12.7 --- Abs10 Absorption coefficient at T=10000K(1)
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Note (1): α/ρ3 in units of cm-1*amagat-3 where
amagat=2.68678*1019cm-3.
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Acknowledgements:
Piotr Kowalski, p.kowalski(at)fz-juelich.de
(End) Patricia Vannier [CDS] 27-Jun-2014