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How to accurately model IR spectra of nanosized silicate grains

Published online by Cambridge University Press:  12 October 2020

Joan Mariñoso Guiu
Affiliation:
Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB). Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain email: [email protected]
Antoni Macià
Affiliation:
Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB). Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain email: [email protected]
Stefan T. Bromley
Affiliation:
Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB). Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain email: [email protected] Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
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Abstract

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We assess the accuracy of various computational methods for obtaining infrared (IR) spectra of nanosized silicate dust grains directly from their atomistic structure and atomic motions. First, IR spectra for a selection of small nanosilicate clusters with a range of sizes and chemical compositions are obtained within the harmonic oscillator approximation employing density functional theory (DFT) based quantum chemical calculations. To check if anharmonic effects play a significant role in the IR spectra of these nanoclusters, we further obtain their IR spectra from finite temperature DFT-based ab initio molecular dynamics (AIMD). Finally, we also study the effect of temperature on the broadening of the obtained IR spectra peaks in larger nanosilicate grains with a range of crystallinities. In this case, less computationally costly classical molecular dynamics simulations are necessary due to the large number of atoms involved. Generally, we find that although DFT-based methods are more accurate, surprisingly good IR spectra can also be obtained from classical molecular dynamics calculations.

Type
Contributed Papers
Copyright
© International Astronomical Union 2020

References

Henning, T 2010, ARA&A, 48, 21 CrossRefGoogle Scholar
Li, A. & Draine, B. T. 2001, ApJ, 500, L213 CrossRefGoogle Scholar
Macià, A., Lazauskas, T., Woodley, S. M., & Bromley, S. T. 2019, ACS Earth and Space Chemistry, 3, 2390 Google Scholar
Plane, J. M. C 2001, Chem. Soc. Rev., 41, 6507 CrossRefGoogle Scholar
Zamirri, L., Macià, A., Mariñoso, J., Ugliengo, P., & Bromley, S. T. 2019, ACS Earth and Space Chemistry, 3, 2323 CrossRefGoogle Scholar