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Janus monolayers and their van der Waals heterostuctures are investigated by hybrid density functional theory calculations.

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A theoretical imaging method is used to study the induced effects of a spherical surface on the photodetached electron spectra of a mono-atomic negative ion (H − ). Analytical formulas are derived for the detached electron flux and the total photodetachment cross section. The radius of the spherical surface strongly affects the spectra of the flux as well as the cross section. The analysis of the spectra reveals that the curvature of the surface controls the oscillations in the spectra, and the plane wall case reported in Afaq and Du (2007 J. Phys. B: At. Mol. Opt. Phys. 40 1309) is a special case of the spherical surface.

Particulate matter (PM) plays a vital role in altering air quality, human health, and climate change. There are sparse data relevant to PM characteristics in urban environments of the Middle East, including Peshawar city in Pakistan. This work reports on the morphology and composition of PM in two size fractions (PM2.5 and PM10) during November 2016 in Peshawar. The 24 hous mass concentration of PM2.5 varied from 72 μg m−3 to 500 μg m−3 with an average value of 286 μg m−3. The 24 hours PM10 concentration varied from 300 μg m−3 to 1440 μg m−3 with an average of 638 μg m−3. The morphology, size, and elemental composition of PM were measured using Fourier Transform Infra Red (FT-IR) Spectroscopy and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) Spectroscopy. The size of the analyzed particles by EDX ranged from 916 nm to 22 μm. Particles were classified into the following groups based on their elemental composition and morphology: silica (12%), aluminosilicates (23%), calcium rich (3%), chloride (2%), Fe/Ti oxides (3%), carbonaceous (49%), sulfate (5%), biogenic (3%). The major identified sources of PM are vehicular emissions, biomass burning, soil and re-suspended road dust, biological emissions, and construction activities in and around the vicinity of the sampling site.

Structural and optoelectronic properties of BaThO3 cubic perovskite are calculated using all electrons full potential linearized augmented plane wave (FP-LAPW) method. Wide and direct band gap, 5.7 eV, of the compound predicts that it can be effectively used in UV based optoelectronic devices. Different characteristic peaks in the wide UV range emerges mainly due to the transition of electrons between valance band state O-p and conduction band states Ba-d, Ba-f, Th-f and Th-d.Comment: 20 pages and 7 figure