We present theoretical and experimental evidence of an anomalous surface corrugation behavior in He-KCl(001) for incidence along ⟨110⟩. When the He normal energy decreases below 100 meV, i.e., He-surface distances Z>2 Å, the corrugation unexpectedly increases up to an impressive ≳85%. This is not due to van der Waals interactions but to the combination of soft potential effects and the evolution of He-cation and He-anion interactions with Z. This feature, not previously analyzed on alkali-halide surfaces, may favor the alignment properties of weakly interacting overlayers.
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http://dx.doi.org/10.1103/PhysRevLett.125.096101 | DOI Listing |
J Phys Chem C Nanomater Interfaces
December 2024
Instituto IMDEA Nanociencia, Calle Faraday 9, 28049 Madrid, Spain.
Graphene adsorbed on Ru(0001) has been widely used as a template for adsorbing and isolating molecules, assembling organic-molecule structures with desired geometric and electronic properties and even inducing chemical reactions that are challenging to achieve in the gas phase. To fully exploit the potential of this substrate, for example, by being able to tune a graphene-based catalyst to perform optimally under specific conditions, it is crucial to understand the factors and mechanisms governing the molecule-substrate interaction. To contribute to this effort, we have conducted a combined experimental and theoretical study of the adsorption of cyanomethyl radicals (-CHCN) on this substrate below room temperature by performing scanning tunneling microscopy experiments and density functional theory simulations.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
School of Physics and Optoelectronics, South China University of Technology, Guangzhou 510641, China.
Linear optical diffraction of light is a basic natural phenomenon subject to a long history study and it obeys the well-known reciprocity in transport. In this work we report observation of synergistic nonreciprocal linear and nonlinear diffraction of a Ti:sapphire femtosecond laser beam against a periodic poled lithium niobate (PPLN) thin plate nonlinear grating with a front surface corrugated with a shallow grating of a depth only 67 nm and a smooth back surface. A high peak power pump laser beam shining upon the geometrically asymmetric nonlinear grating from either the front surface and back surface will both cause significant second-order nonlinear (2nd-NL) Raman-Nath diffraction and Cerenkov radiation, in addition to apparent linear optical diffraction and modest third-order nonlinear (3rd-NL) spectral broadening.
View Article and Find Full Text PDFJ Chem Theory Comput
December 2024
Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China.
Global potential energy surface (PES) exploration provides a unique route to predict the thermodynamic and kinetic properties of unknown materials, but the task is highly challenging for systems with tight covalent bonds. Here, we develop the local-softening stochastic surface walking (LS-SSW) method for scanning corrugated PESs. LS-SSW transforms the vibrational mode space of a system by adding pairwise penalty potentials with a self-adaption mechanism, which helps to delocalize and soften the strong local modes.
View Article and Find Full Text PDFBiomimetics (Basel)
November 2024
College of Civil Engineering, Jilin Jianzhu University, Changchun 130118, China.
With the aiming of solving problems with the existing ordinary excavator buckets used in the process of operations (such as heavy digging resistance, ease of adhesion, and others), seven types of bionic buckets and a prototype bucket were designed, based on the contractile-state curve of the earthworm head and the contour curve of the pangolin claw toe. The digging processes of the buckets were simulated using the discrete element method. The results show that, compared with the prototype buckets, all seven types of bionic buckets have significant drag reduction effects at the same digging depth, and the drag reduction effects increase with the decrease of digging speed.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08540, USA.
The interplay between thin film hydrodynamics and solidification produces formidably intricate geophysical structures, such as stalactites and icicles, whose shape is a testimony of their long growth. In simpler settings, liquid films can also produce regular patterns. When coated on the underside of a flat plate, these films are unstable and yield lattices of drops following the Rayleigh-Taylor instability.
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