Theoretical study of infrared spectra of iodide molecules on NaCl surfaces

Maxime Infuso (1) , Florent Louis (2) , Denis Duflot (1) , Céline Toubin (1)

1 PCMT - Physico-Chimie Moléculaire Théorique
2 PC2A - Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522

Iodine, when released into the environment, contributes to the oxidizing capacity of the atmosphere through the catalytic destruction of ozone [1, 2]. Iodine-131 can be released during a severe nuclear accident and can be carcinogenic for humans [3]. In the literature, there are missing pieces of knowledge about interactions between iodinated compounds and aerosols. In this context, this work consists in investigating the adsorption on sea salt aerosols of gaseous methyl iodide (CH₃I), diiodomethane (CH₂I₂), and water. We have used two different methods: a periodic approach using Quantum ESPRESSO [4, 5] and a cluster QM/QM' approach using the ONIOM method [6] from Gaussian 16 [7]. We have computed the adsorption energies and the shift in vibrational frequencies, due to adsorption. We have shown that the vibrational frequency shifts are small, mainly because there is no strong coupling between the adsorbates and the NaCl (001) surface, as illustrated by the low values of the adsorption energies.

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(4) Giannozzi, P. et al. J. Phys. Condens. Matter 2009, 21, 395502
(5) Giannozzi, P. et al. J. Phys. Condens. Matter 2017, 29, 465901
(6) Svensson, M.; Humbel, S.; Froese, R. D.; Matsubara, T.; Sieber, S.; Morokuma, K. J. Phys. Chem. 1996, 100, 19357-19363
(7) Frisch, M. J. et al. Gaussian 16 Revision B.01, Gaussian Inc. Wallingford CT, 2016

Domaines: Chimie théorique et/ou physique; Chimie-Physique [physics.chem-ph]

Maxime Infuso, Florent Louis, Denis Duflot, Céline Toubin. Theoretical study of infrared spectra of iodide molecules on NaCl surfaces. Réunion annuelle du GDR ThéMS, Dec 2020, Visioconférence, France. ⟨hal-03113811⟩