The interaction of water molecules and hydroxyl groups with titanium dioxide (TiO2) surfaces is ubiquitous and very important in anatase nanopartide photocatalytic processes. Infrared spectroscopy, assisted by ab initio calculations of vibrational frequencies, can be a powerful tool to elucidate the mechanisms behind water adsorption. However, a straightforward comparison between measurements and calculations remains a challenging task because of the complexity of the physical phenomena occurring on nanopartide surfaces. Consequently, severe computational approximations, such as harmonic vibrational ones, are usually employed. In the present work we partially address this complexity issue by overcoming some of the standard approximations used in theoretical simulations and employ the Divide and Conquer Semiclassical Initial Value Representation (DC-SCIVR) molecular dynamics. This method allows to perform simulations of vibrational spectra of large dimensional systems accounting not only for anharmonicities, but also for nuclear quantum effects. We apply this computational method to water and deuterated water adsorbed on the ideal TiO2 anatase(101) surface, contemplating both the molecular and the dissociated adsorption processes. The results highlight not only the presence of an anharmonic shift of the frequencies in agreement with the experiments, but also complex quantum mechanical spectral signatures induced by the coupling of molecular vibrational modes with the surface ones, which are different in the hydrogenated case from the deuterated one. These couplings are further analyzed by exploiting the mode subdivision performed during the divide and conquer procedure.

Quantum Anharmonic Calculations of Vibrational Spectra for Water Adsorbed on Titania Anatase(101) Surface: Dissociative versus Molecular Adsorption / M. Cazzaniga, M. Micciarelli, F. Gabas, F. Finocchi, M. Ceotto. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - 126:29(2022 Jul 28), pp. 12060-12073. [10.1021/acs.jpcc.2c02137]

Quantum Anharmonic Calculations of Vibrational Spectra for Water Adsorbed on Titania Anatase(101) Surface: Dissociative versus Molecular Adsorption

M. Cazzaniga
Primo
;
M. Micciarelli
Secondo
;
F. Gabas;M. Ceotto
Ultimo
2022

Abstract

The interaction of water molecules and hydroxyl groups with titanium dioxide (TiO2) surfaces is ubiquitous and very important in anatase nanopartide photocatalytic processes. Infrared spectroscopy, assisted by ab initio calculations of vibrational frequencies, can be a powerful tool to elucidate the mechanisms behind water adsorption. However, a straightforward comparison between measurements and calculations remains a challenging task because of the complexity of the physical phenomena occurring on nanopartide surfaces. Consequently, severe computational approximations, such as harmonic vibrational ones, are usually employed. In the present work we partially address this complexity issue by overcoming some of the standard approximations used in theoretical simulations and employ the Divide and Conquer Semiclassical Initial Value Representation (DC-SCIVR) molecular dynamics. This method allows to perform simulations of vibrational spectra of large dimensional systems accounting not only for anharmonicities, but also for nuclear quantum effects. We apply this computational method to water and deuterated water adsorbed on the ideal TiO2 anatase(101) surface, contemplating both the molecular and the dissociated adsorption processes. The results highlight not only the presence of an anharmonic shift of the frequencies in agreement with the experiments, but also complex quantum mechanical spectral signatures induced by the coupling of molecular vibrational modes with the surface ones, which are different in the hydrogenated case from the deuterated one. These couplings are further analyzed by exploiting the mode subdivision performed during the divide and conquer procedure.
titania, water, IR
Settore CHIM/02 - Chimica Fisica
H2020_ERC15MCEOT_M - Divide and Conquer ad initio semiclassical molecular dynamics for spectropic calculations of complex systems (SEMICOMPLEX) - CEOTTO, MICHELE - H2020_ERC - Horizon 2020_Europern Research Council - 2015
FARE18MCEOT_01 - Studio teorico-computazionale della bonifica fotocatalitica di atmosfere inquinate (QURE) - CEOTTO, MICHELE - FARE -FARE Ricerca in Italia - 2018
19-lug-2022
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/938865
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