School of Physics, Shandong University, 27 Shanda Nanlu, Jinan, Shandong 250100, P. R. China.
Published: November 2017
AI Article Synopsis
Article Abstract
The CO adsorption and dynamic behaviors on single crystal anatase TiO(101) surfaces were investigated by UHV-FTIRS and first-principles calculations. The IRRAS results at 90 K show that the ν(OCO) asymmetric stretching vibration of adsorbed CO exhibits band splitting at rather low CO coverage in p-polarized IR spectra for the IR beam incident along the [101[combining macron]] direction. Co-adsorbed CO can prevent such band splitting. Ab initio molecular dynamics (AIMD) simulations revealed that the adsorbed CO at finite temperature does not keep a stationary adsorption state but keeps a certain swing motion: one end of the linear CO molecule binds to surface Ti sites and the other end swings within the (010) plane with a tilted angle distribution ranging from 10° to 60° relative to the [101[combining macron]] direction. By suggesting a statistical model, we confirmed that it is the swing motion that results in the band splitting phenomenon of CO vibration in IR spectra. The co-adsorbed CO decreases the swing angle distribution ranging from 10° to 45° through the intermolecular interaction between CO and CO, leading to the disappearance of CO band splitting.
The cross talk and power consumption of the 2 × 2 optical switch is a key metric in the design of large-scale photonic integrated circuits (PICs). We build a theoretical model of a 2 × 2 Mach-Zehnder interferometer (MZI) optical switch, taking into account both imbalances in the arm loss and the coupler splitting ratio. The splitting ratio imbalance requirement for a given switch cross talk is summarized, which provides a guideline for the switch design.
Hydrogen evolution reaction (HER) is a key reaction in electrochemical water splitting for hydrogen production leading to the development of potentially sustainable energy technology. Importantly, the catalysts required for HER must be earth-abundant for their large-scale deployment; silicates representing one such class. Herein, we have synthesized a series of transition mono- and bi- metal metasilicates (with SO32- group) using facile wet-chemical method followed by calcination at a higher temperature.
The rotational spectra of a mixture of 2,4-pentanediol (PDL) isomers, comprising both the meso isomers [(2R, 4S) and (2S, 4R)] and the racemic isomers [(2R, 4R) and (2S, 4S)], were recorded using a chirped-pulse Fourier transform microwave spectrometer coupled to a supersonic jet expansion. The conformational landscapes of meso- and racemic-PDL were examined using the Conformer-Rotamer Ensemble Sampling Tool and high-level quantum chemical calculations, generating 26 and 25 conformers, respectively. Five sets of rotational transitions were observed and assigned, with two attributed to meso-PDL and the remaining three attributed to racemic-PDL.
Two-dimensional van der Waals heterojunction materials have demonstrated significant potential for photocatalytic water splitting in hydrogen production, owing to their distinct electronic and optical properties. Among these materials, direct Z-scheme heterojunctions have attracted considerable attention in recent research. In this study, a novel CdO/ZrSSe heterojunction is designed using first-principles calculations.
Inorganic lead-free metal halide perovskites have garnered much attention as low-toxicity alternatives to lead halide perovskites for luminescence and photovoltaic applications. However, the electronic structure and properties of these materials, including the composition dependence of the band structure, spin-orbit coupling, and Zeeman effects, remain poorly understood. Here, we investigated vacancy-ordered CsBiX (X= Cl, Br) perovskite nanocrystals using magnetic circular dichroism spectroscopy.
