IBER 2023

First-principles computations on guest-host (lattice) systems: He inclusion in hydrates

6 Sept 2023, 18:35

1h

Department of Physics, University of Coimbra

Poster Communication Poster Session

Speaker

Dr Rita Prosmiti (Institute of Fundamental Physics (IFF-CSIC))

Description

He hydrates present an intriguing and relatively unexplored systems. As they may have significant implications in fields such as planetary science, exploration of novel ice phases, such as ultra-low density ices or superionic water ice, and the development of innovative materials with distinct properties and applications, such as solid electrolyte in batteries, understanding their fundamental properties is crucial for their future exploitation.
Computational investigations on the He@hydrates were motivated by the recent experimental synthesis of He@sII [1], and in relation with the emerging research on new low-density ice polymorphs [2]. We performed quantum chemistry computations considering both aperiodic ice/clathrate-like finite-size structures [3,4] and periodic 3D crystal frameworks [5]. In this way, we demonstrated the importance of conducting a systematic benchmark study of conventional and modern DFT-D approaches, including fundamental units (e.g. He-H${}_2$O) and building block clathrate cages (e.g. 5${}^{12}$ or 5${}^{12}$6${}^4$) or ice channels present in the most common sI, sII and sH clathrate hydrates or ice II and Ih. In turn, we analysed the stability of the cages forming the He@sII clathrate, considering single and multi-occupancy [6], through thermochemical calculations at a range of T-P conditions comparable to the experiment [1] . Finally, we explored the effects on the encapsulation of He atoms in the sI/sII crystal lattices by computing structural, mechanical and energetic properties in both empty and He-filled systems. For a more direct comparison with measurements on He@sII structural properties, multiple cage occupancy, similar to those established by diffraction experiments [1], is considered [7]. All these insights serve to better understand the role of the entire guest-guest, guest-host and host-host interactions in the stabilization of such clathrate hydrates, they address accuracy issues on weakly-bound systems, providing valuable reference data that can be utilized for developing future predictive data-driven models using either traditional fitting or emergent machine-learning techniques.

1 W. F. Kuhs, T. C. Hansen and A. Falenty, J. Phys. Chem. Lett., 2018, 9, 3194–3198.
2 Y. Liu and L. Ojamäe, Phys. Chem. Chem. Phys., 2018, 20, 8333–8340.
3 R. Yanes-Rodríguez, D. J. Arismendi-Arrieta and R. Prosmiti, J. Chem. Inf. Model., 2020, 60, 3043–3056.
4 R. Yanes-Rodríguez and R. Prosmiti, Phys. Chem. Chem. Phys., 2022, 24, 1475–1485.
5 R. Yanes-Rodríguez,A. Cabrera-Ramírez and R. Prosmiti, Phys. Chem. Chem. Phys., 2022, 24, 13119-13129.
6 R. Yanes-Rodríguez and R. Prosmiti, Phys. Chem. Chem. Phys., 2023, 25, DOI:10.1039/D2CP00603D.
7 R. Yanes-Rodríguez and R. Prosmiti, Phys. Chem. Chem. Phys., 2023, submitted.