Astrochemistry

Binding Energy Evaluation Platform: A Database Of Quantum Chemical Binding Energy Distributions For The Astrochemical Community

By Keith Cowing
astro-ph.IM
July 27, 2022
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Binding Energy Evaluation Platform: A Database Of Quantum Chemical Binding Energy Distributions For The Astrochemical Community
Binding energy distributions for Group D, ASW – X systems, using HF-3c/MINIX geometries except for CO (M05/def2-TZVP). ZPVE correction has been included only for C2H2, see 3.2. The energy has been computed at ω-PBE/def2- TZVP level of theory for all species except CH4 (TPSSH/def2-TZVP). D3BJ dispersion correction has been applied to all DFT energies.

The quality of astrochemical models is highly dependent on reliable binding energy (BE) values that consider the morphological and energetic variety of binding sites on the surface of ice-grain mantles.

Here, we present the Binding Energy Evaluation Platform (BEEP) and database that, using quantum chemical methods, produces full BE distributions of molecules bound to an amorphous solid water (ASW) surface model. BEEP is highly automatized and allows to sample binding sites on set of water clusters and to compute accurate BEs. Using our protocol, we computed 21 BE distributions of interstellar molecules and radicals on an amorphized set of 15-18 water clusters of 22 molecules each. The distributions contain between 225 and 250 unique binding sites.

We apply a Gaussian fit and report the mean and standard deviation for each distribution. We compare with existing experimental results and find that the low and high coverage experimental BEs coincide well with the high BE tail and mean value of our distributions, respectively. Previously reported single BE theoretical values are broadly in line with ours, even though in some cases significant differences can be appreciated.

We show how the use of different BE values impact a typical problem in astrophysics, such as the computation of snow lines in protoplanetary discs. BEEP will be publicly released so that the database can be expanded to other molecules or ice-models in a community effort.

Giulia M. Bovolenta, Stefan Vogt-Geisse, Stefano Bovino, Tommaso Grassi

Comments: Accepted on ApJS
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2207.13095 [astro-ph.IM] (or arXiv:2207.13095v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2207.13095
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Submission history
From: Giulia Bovolenta
[v1] Tue, 26 Jul 2022 14:08:57 UTC (3,931 KB)
https://arxiv.org/abs/2207.13095
Astrobiology, Astrochemistry

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