Search

Many current deep neural network (DNN) models only focus on straightforward optimization over the given database. However, most numerical fitting procedures depart from physical laws. By introducing the concept of "catalysis" from physical chemistry, we propose that the physical correlations among molecular properties could spontaneously act as a catalyst in the DNNs, which increases the accuracy, and more importantly, guides the DNNs in the right way. These Catalysis-DNNs (Cat-DNNs) could precisely predict both the ground and excited-state properties, especially the molecules' screening with singlet fission character. We show that traditional machine learning metrics are not suitable for evaluating model accuracy in physical–chemical tasks and issue new physical errors. We believe that the agile transfer of fundamental physics or chemistry domain knowledge, like the catalyst, could significantly benefit both the architecture and application of artificial intelligence technology in the future. [ABSTRACT FROM AUTHOR]

Hybrid organic–inorganic metal halides have emerged as highly promising materials for a wide range of applications in optoelectronics. Incorporating chiral organic molecules into metal halides enables the extension of their unique optical and electronic properties to chiral optics. By using chiral (R)‐ or (S)‐methylbenzylamine (R‐/S‐MBA) as the organic component, we synthesized chiral hybrid copper halides, (R‐/S‐MBA)2CuCl4, and investigated their optical activity. Thin films of this material showed a record anisotropic g‐factor as high as approximately 0.06. We discuss the origin of the giant optical activity observed in (R‐/S‐MBA)2CuCl4 by theoretical modeling based on density functional theory (DFT) and demonstrate highly efficient second harmonic generation (SHG) in these samples. Our study provides insight into the design of chiral materials by structural engineering, creating a new platform for chiral and nonlinear photonic device applications of the chiral hybrid copper halides. [ABSTRACT FROM AUTHOR]

A structurally stable silicon allotrope is predicted by means of first principles calculations. This new structure is composed of a six-membered ring, a five-membered ring and a three-membered ring with the space group PA3̅ and fvs topology, which is named fvs-Si48. The calculations of geometrical, vibrational, and electronic and optical properties reveal that fvs-Si48 has good mechanical stability with a mass density of 1.86 g cm−3. More importantly, it is a semiconductor with a direct band gap of 2.15 eV. From the analysis of its optical properties, there is the possibility of its synthesis in theory. This fvs-Si48 could have a wide range of applications in photo catalysts, optoelectronics, hydrogen storage and aerospace engineering. [ABSTRACT FROM AUTHOR]

Abstract: A new carbon porous allotrope is investigated by the first principle calculations. The allotrope consists of 12 atoms in a tetragonal cell and displays a P 4 ‾ 2 m symmetry (termed as tP−C12 carbon) with a mass density of 2.18 g/cm3. Its phonon dispersion possessing no imaginary frequency indicates that tP−C12 is dynamically stable. Furthermore, its elastic constants also demonstrate the mechanical stability. Its bulk modulus is 181 GPa. The electronic band structure reveals that it is a metallic phase. X‐ray diffraction patterns and Raman spectra are also theoretically calculated to provide more characterizations for future experimental observations. Due to its porous and metallic properties, this new carbon allotrope may possess hydrogen storage and catalysis application. [ABSTRACT FROM AUTHOR]

Keywords: chirality; circular dichroism; hybrid copper halides; nonlinear optics; second harmonic generation EN chirality circular dichroism hybrid copper halides nonlinear optics second harmonic generation 21262 21262 1 09/16/21 20210920 NES 210920 Because the interference is not considered, formula (4) in this Communication is not really applicable for the I d SB eff sb i estimation of the hybrid metal halide thin film. Chirality, circular dichroism, hybrid copper halides, nonlinear optics, second harmonic generation. [Extracted from the article]

Chirality, circular dichroism, hybrid copper halides, nonlinear optics, second harmonic generation Keywords: chirality; circular dichroism; hybrid copper halides; nonlinear optics; second harmonic generation EN chirality circular dichroism hybrid copper halides nonlinear optics second harmonic generation 21094 21094 1 09/16/21 20210920 NES 210920 Because the interference is not considered, formula (4) in this Communication is not really applicable for the I d SB eff sb i estimation of the hybrid metal halide thin film. [Extracted from the article]