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The total spin number S is not a ‘good quantum number for’ the Heisenberg model with singleion anisotropy, so the Hamiltonian eigenstates with different S may form linear combinations. Sometimes it is assumed that S can be used as an ‘approximate quantum number’, though some results show that mixing of S-states is important in investigations of magnetic molecules. Some small spin systems with the dihedral symmetry are analyzed to investigate different schemes of mixing and its dependence on the anisotropy parameter. The results show various behavior of the magnetic state mixing. The mean (over a state) value of total spin is quite stable for the ground state, but in other cases this dependence is nonlinear and sometimes non-monotonic.

Laser-induced breakdown of an optically trapped nanoparticle is a unique system for studying cavitation dynamics. It offers additional degrees of freedom, namely the nanoparticle material, its size, and the relative position between the laser focus and the center of the optically trapped nanoparticle. We quantify the spatial and temporal dynamics of the cavitation and secondary bubbles created in this system and use hydrodynamic modeling to quantify the observed dynamic shear stress of the expanding bubble. In the final stage of bubble collapse, we visualize the formation of multiple submicrometer secondary bubbles around the toroidal bubble on the substrate. We show that the pattern of the secondary bubbles typically has its circular symmetry broken along an axis whose unique angle rotates over time. This is a result of vorticity along the jet towards the boundary upon bubble collapse near solid boundaries.

Summary: Computer supported design of materials with tailored properties is an important part of computational science so that developments of new effective algorithms is a key issue. Molecular magnetism deals with complex objects described by the quantum physics and their simulations come up against the computational constraints. In this work, we consider a numerical version of a recently developed hybrid approach that combines the ab initio DFT method with the exact diagonalization of the microscopic Hubbard model (HM). The latter avoids the prior perturbative framework but increases computing resources needed for solving the eigenvalue problem of the matrix representation of HM. We demonstrate that in the case of the ring‐shape molecular nanomagnets the computational demands can be curbed due to efficient numerical matrix construction algorithms provided. These algorithms pertain both to the calculation of the single nonzero matrix elements and to their localization in the final sparse matrix that is subsequently diagonalized. Their implementation executed on a simple six‐core‐computer system and the Mathematica environment leads to a significant gain in the computing time for the exemplary chromium‐based molecule denoted Cr8$$ {}_8 $$, running the code sequentially. We claim, referring to the numerical diagonalization of the spin Hamiltonian matrices, that the parallelization flaws related to the high‐level programming approach can be all removed, porting the code to the appropriate HPC environment. A prospective implementation of the code, based on some dedicated and optimized mathematical libraries, will ultimately open a window for further applications of the Hubbard model in molecular magnetism. [ABSTRACT FROM AUTHOR]

This article describes benefits of the application of zinc oxide submicron particles (ZnO SMPs), zinc oxide nanoparticles (ZnO NPs) and ZnO NPs combined with silver NPs (ZnO + Ag NPs) in chrysanthemum micropropagation. Single node explants of Chrysanthemum × morifolium (Ramat.) Hemsl. ‘UTP Burgundy Gold (UBG)’ and ‘UTP Pinky Gold (UPG)’ were inoculated on the Murashige and Skoog (MS) medium and treated with 100 mg · L−1, 200 mg · L−1, or 400 mg · L−1 ZnO SMPs, ZnO NPs (1.5% H2O), ZnO NPs (6% H2O), ZnO + 0.1% Ag NPs (1.5% H2O), ZnO + 0.1% Ag NPs (6% H2O), ZnO + 1% Ag NPs (1.5% H2O) and ZnO + 1% Ag NPs (6% H2O). Generally, the tested materials stimulated the growth and development of plantlets. In ‘UBG’, the most prominent treatments affecting increases in the number of leaves, micropropagation coefficient, shoot length and shoot FW/DW weight included 400 mg · L−1 ZnO SMPs and 100 mg · L−1 ZnO NPs (6% H2O). In ‘UPG’, the treatments with 200 mg · L−1 ZnO + 0.1% Ag NPs (6% H2O) and 200 mg · L−1 ZnO + 1% Ag NPs (6% H2O) were the most successful. The latter treatment stimulated an intensive development of root systems in the two studied cultivars. High values of leaf area, perimeter and width were reported in both cultivars for 400 mg · L−1 ZnO + 1% Ag NPs (6% H2O). As compared to the control, the treated plants were characterised by a similar or, most often, lower content of chlorophylls and carotenoids. The randomly amplified polymorphic DNA (RAPD) and start codon targeted polymorphism (SCoT) marker system analyses of the 400 mg · L−1 ZnO SMPs/ZnO NPs/ZnO + Ag NPs-treated chrysanthemums confirmed their genetic fidelity with the control plants. The obtained results can be implemented in the commercial large-scale production of chrysanthemums.

Two tetranuclear mixed-valent clusters, [MnII3MnIIICl(Ph3CCOO)4(CH3OCH2CH2O)4(CH3CN)]·0.4C6H5CH3·0.6CH3CN (1) with an unprecedented [MnII3MnIII] core and [MnII2MnIII2Cl4(CH3OCH2CH2O)6] (2), were synthesized and characterized by single-crystal X-ray diffraction and magnetic measurements. Their properties were analyzed in the framework of phenomenological modelling and DFT calculations, showing acceptable agreement between theory and experiment. Both building blocks [MnII3MnIII] and [MnII2MnIII2] provide good examples of bipartite systems with the lowest ST = 1/2 and highest ST = 9 magnetic ground states available for them. The topology of the magnetic interactions in the [MnII3MnIII] core provides a suitable template for the molecular qubit implementation and the stability of the spin-1/2 ground state strongly depends on the antiferromagnetic MnII–MnII coupling. [ABSTRACT FROM AUTHOR]

Zero-temperature limits of the local and global thermodynamic quantities in the nine-membered antiferromagnetic s = 3/2 spin ring are investigated by means of numerical exact diagonalization. An anisotropic Heisenberg model with tunable bond defect reflecting continuously varying topology (from closed to open ring) is exploited. The frustrated and non-frustrated phases are identified in the ground-state phase diagram determined by a bond-defect strength and magnetic field. Near the phase boundaries significance of the thermal fluctuations affecting the estimates of the local magnetic quantities found earlier at T = 1 K is revealed. For the global quantities the effects of thermal fluctuations are found much weaker. A sequence of the local magnetic moments is analysed and their experimental verification at the edges of the non-frustrated and within the entire frustrated phase is suggested at sufficiently low temperature. [ABSTRACT FROM AUTHOR]

The research addressed the effect of gibberellic acid (GA3) on growth and flowering of Ajania pacifica /Nakai/ Bremer et Humphries ‘Bea’. The vegetative growth lasted for 8 weeks in glasshouse, under natural long day and from August 15 - under natural short day. The plants were divided into four groups: 1 - the plants sprayed with distilled water (control combination); 2, 3 and 4 - the plants sprayed with GA3 ones, twice and thrice, respectively, starting from the 5th week of growth, and then in the 6th and 7th week, successively. Each of the group was divided into two subgroups: the first one treated with GA3 at concentration of 250 mg·dm-3 and the second with 500 mg·dm-3. It was observed that double spraying with GA3 accelerated the buds development of Ajania pacifica, thus shortened the cultivation time by about two days. Treatment with GA3 at concentration 500 mg·dm-3 stimulated the elongation of shoots more than treatment with GA3 at 250 mg·dm-3. The plants sprayed twice were longer than the control and then those sprayed one time. However, elongation of shoots was not remarkable; corymbs were shorter, narrower, and contained lesser number of inflorescences. The present study indicates the specificity of the response of Ajania pacifica to GA3 treatment, which appears to be different from other ornamental species.