Report on the outcomes of a Short-Term Scientific Mission

Action number: CA21101

Applicant name: Michael Hütter

Details of the STSM

Title: Photochemical investigation of solid-phase MgO nanocrystals

Start and end date: 30/07/2023 to 19/08/2023

Description of the work carried out during the STSM

During the initial phase of the Short-Term Scientific Mission (STSM), an exploration into the behaviour of gas-phase MgO nanocrystals was conducted. Specifically, two distinct models, Mg18O18 and Mg32O32, each encompassing various spin configurations (singlet and triplet) and diverse defect scenarios, were analysed utilizing established quantum chemical methodologies, such as Density Functional Theory (DFT). This process aimed to pinpoint an ideal model system that demonstrated promising reactivity potential.

Once a suitable model was identified, the focus shifted toward analysing its reactivity with differing oxygen molecule conformations positioned on the crystal’s surface. The objective was to find the optimal configuration that would promote the desired chemical reaction. To validate the accuracy and efficiency of the calculations, two different basis sets were employed: a smaller one and a larger one. This comparative approach aimed to determine whether accurate outcomes could be achieved with a reduced basis set.

Subsequently, the investigation progressed to examine the interactions of these MgO nanocrystals with water molecules. This phase of the research, regrettably, presented unexpected challenges, as in the computational process convergence issues were encountered, predominantly stemming from the redundant coordinate system and the linear search algorithm as implemented within the Gaussian software. While addressing the latter complication is rather straightforward, finding an elegant solution for the former requires a manual definition of the appropriate redundant coordinates.
Regretfully, due to unforeseen health troubles, the Grantee found it necessary to return to their home country after ten days. Seeking the expertise of a medical professional well-versed in their medical history was paramount. Given the nature of the required medical tests that extended over multiple days, the Grantee made the decision not to return to Prague, opting instead to continue their research and calculations from home.

In the subsequent phase, the investigation delved into locating the transition state of the chemical reaction involving MgO nanocrystals, oxygen molecules, and water molecules. This exploration was facilitated using the QST2 algorithm within the Gaussian software. The objective was to attain a more comprehensive understanding of the reaction’s intricate mechanics as a whole, shedding light on the transformative process occurring at the molecular level.

Description of the STSM main achievements and planned follow-up activities

The primary objective of this Short-Term Scientific Mission (STSM) was to delve into the intricate interplay between structure and properties exhibited by atomically dispersed catalysts, focusing particularly on doped MgO nanocrystals. This pursuit entailed a comprehensive exploration, involving the computational modelling of MgO nanocrystals of varying sizes. The investigation extended to the deliberate introduction of diverse defects at crucial points—be it corners, edges, or surfaces of the nanocrystals. Furthermore, the research encompassed the modelling of oxygen molecule conformations adsorbed onto the crystal’s surface.

Through the subsequent introduction of water into these meticulously constructed systems, it became possible to theoretically examine the chemical reactions akin to those observed experimentally within Prof. Oliver Diwald’s research group, which aligns well with Building Objective 2. While certain computations extended beyond their anticipated durations (as previously detailed), it precluded the exploration beyond the confines of the static approach founded on minimized cluster models.

Looking ahead, the Grantee’s ambition to delve into the implications of dynamic lattice vibrations on reactivity remained unfulfilled within the scope of this work. This avenue of investigation, however, retains its potential for future exploration.

Moreover, the pursuit of Capacity Building Objective 6 was concurrently undertaken. The Grantee capitalized on the opportunity to collaborate with Dr. Eva Muchová in Prague during the initial 10 days of the Grant period. This collaboration significantly extended the Grantee’s knowledge and skill set. Regrettably, the unexpected turn of events compelled the Grantee to return to their home country, necessitating a shift to remote work, with online meetings serving as the conduit for sustained supervision and guidance.

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