Recently, nanoparticles based on rare earth fluorides have been widely investigated due to their possible medical and spintronic applications, where it is desirable to know the magnetic moment volume distribution. However, this feature is hard to find out from the experiments, so we employ ab initio spin-polarized calculations for this purpose in order to find out the tendencies and common features in three different compounds. In the present work, the nanoparticles of dipole magnets with different sizes, namely TbF₃, DyF₃ and HoF₃, were simulated, and optimized structures were found. We present the optimized structures for the particles with various sizes, as well as for slabs constructed from same compounds. Lastly, for optimized geometries, the analysis of magnetic moments’ distribution over the nanoparticles and slabs volume was performed.

In this study, density functional theory (DFT) is employed to analyze the properties of 16 azobenzene derivatives,assessing their potential as wettability switching materials. Inspired by K. Ichimura’s 2001 report onazobenzene-modified surface wettability, we explore the impact of photoisomerization-induced changes inmolecular dipole moments between cis and trans configurations of different azobenzene derivatives. In parentazobenzene molecule this process transforms non-polar molecule into a more hydrophilic cis form. The controlof surface wettability holds immense potential across diverse domains, such as industry, medicine, microbiology,electronics, and materials science. By harnessing this control, we can unlock the potential to createinnovative materials, elevate functionality, and boost efficiency. It enables to enhance product performance,improve adhesion, and achieve precision in liquid handling. Our investigation delves into the structural,electronic, and molecular aspects of all studied molecules utilizing the hybrid B3LYP functional withDFT-D3 dispersion correction and a 6-31++G(d, p) basis set, presenting promising azo-type structures forsurface wettability manipulation. Two azobenzene derivatives emerge as potential candidates, exhibitingtransformations during cis-trans photoisomerization — one towards increased hydrophilicity and the other inthe opposite direction.