Solvation of potassium cation in helium clusters: Density functional theory versus pairwise method

• Published in: Journal of molecular graphics & modelling 2021-07, Vol.106, p.107912-107912, Article 107912
• Main Authors: Laajimi, Maha, Ghalla, Houcine, Mtiri, Safa
• Format: Article
• Language: English
• Subjects: DFT; Doped helium clusters; DOS; Pairwise; Relative stability
• ISSN: 1093-3263; 1873-4243
• DOI: 10.1016/j.jmgm.2021.107912

Microsolvation of a cation in helium quantum solvent is an attractive phenomenon leading generally to the formation of a strongly packed structure known as ‘Snowball’ feature. Here, the lowest energy structures and the relative stability of the solvated potassium cation K+ in helium clusters K+Hen up to the size n = 20 are investigated employing Density Functional Theory (DFT) and pairwise methods. The DFT calculations showed that M05–2X/6–311++G (3df, 2p) level of theory can reproduce properly the experimental data of K+He diatomic potential, whereas, in the pairwise method, the Basin-Hopping Monte Carlo (BHMC) algorithm was applied for the global optimization. The remarkable differences in the lowest energy structures computed in the frame of both methods are shown for K+He11 and K+He12 clusters. The BHMC optimization converged to an icosahedral geometry for n = 12, corresponding to the highest value of the binding energy per atom. For both methods, we have concluded that the first solvation shell is completed at the size n = 15, despite the maximum packing structure obtained at n = 17. Finally, the stability of the potassium doped helium cluster is discussed based on the Density Of States (DOS) curves. [Display omitted] •Microsolvation of potassium cation in helium droplets.•Structures and relative stabilities of K+Hen clusters are investigated.•Pairwise and DFT methods are used.•The snowball feature is obtained for K+He17 cluster.