Chemical Physics Letters最新文献

The selective adsorption mechanism of C-${CdS}_2$ monolayer was revealed using density functional theory. The results show that C-${CdS}_2$ has good adsorption properties for $S{O}_2$, $NO$, $N{H}_3$, $N{O}_2$ and ${Cl}_2$, and all of them are chemisorbed. Under the adsorption of different gas molecules, the electronic structure of C-${CdS}_2$ changed to varying degrees, which provided a theoretical basis for the use of C-${CdS}_2$ as a gas sensor or scavenger for these gases.

We have reported the photophysics of lumichrome (LUM)) in tri-block copolymers micelles of F-127 and P-123, having differences in length of hydrophilic unit. Due to the amphiphilic nature of polymeric micelles, and hydrophilic corona region, we observed the existence of different forms of LUM. We observed an extra emission peak of LUM at ∼ 430 nm and less percentage of existence of the A10 anionic form of LUM in case F-127. From time resolved anisotropy measurement, we have found that the LUM in F-127 micelle faced a more restricted environment than P-123 micelle.

Alkali metals at the A site, coupled with rare earth transition metals featuring partly filled 4f and d orbitals at B and B’ sites in A₂BB’O₆ structure of double perovskites, induce complex d-f electron interactions. Present study explores the rare earth-based double perovskites Ba₂NdNbO₆ and Ba₂NdTaO₆, investigating their structural, optoelectronic, magnetic, and thermoelectric characteristics using first principles method. Computational analyses confirm the stable cubic symmetry and ferromagnetic ground state of both compounds. Negative formation enthalpies underline their thermodynamic stability. Spin polarized electronic band structures reveal direct–indirect degeneracy near the Fermi level, dominated by Nd-4f electrons. Optical investigations indicate absorption onset edges at 4.0 eV and significant absorbance peaks in the 6–10 eV range. Furthermore, the investigation into thermoelectric figure of merit reveals capability of Ba₂NdNbO₆ and Ba₂NdTaO₆ to efficiently convert heat energy in thermoelectric devices. These findings provide information for potential applications of investigated compounds in thermoelectric (TE) and optoelectronic devices; e.g., in optical absorbers, TE coolers and generators, and photonic devices.

Detecting thermal runaway gases in lithium-ion batteries (LIBs) is an effective means of identifying early battery failures and is significant in ensuring the safe operation of LIBs. This work investigated the adsorption characteristics of CO₂, CO, H₂, CH₄, C₂H₂, C₂H₄, and H₂O on intrinsic and Pd-doped HfSSe monolayers using density functional theory (DFT). Our calculations showed that all gases were physically adsorbed on the intrinsic HfSSe monolayer, but the Pd-doped HfSSe monolayer had an enhanced adsorption effect for gas molecules. Additional computations of the band structure, deformation charge density, density of states, and frontier molecular orbitals revealed that the Pd-HfSSe monolayer demonstrated superior CO and C₂H₄ adsorption and sensing capabilities. The analysis of recovery time revealed that Pd-HfSSe may be used as a gas sensor for identifying C₂H₄. This study provides a theoretical basis for applying Pd-HfSSe as a gas sensor to detect thermal runaway gases in LIBs.

This work focuses on the fabrication of chitosan-coated Co₃O₄ nanocomposite (NC) through the utilization of Cissus quadrangularis (CQ) plant extract and the assessment of its biological activities. The plant extract contains various phytoconstituents, which can serve as reducing and stabilizing agents. Moreover, the DPPH test verified the antioxidant activity and the enhanced antibacterial efficacy was tested against S. aureus and E. coli bacterial strains. The hemolysis analysis was also utilized to assess the compatibility with human RBCs. These findings have important implications in the pharmaceutical industry as a possible antioxidant and antibacterial agent.

The kinetics of the recombination and thermal dissociation reactions R + Br (+M) ⇄ RBr (+M) with R = CH₃, CH₂Cl, CHCl₂, CHClBr, CH₂Br and CHBr₂ were theoretically studied over wide temperature and pressure ranges employing unimolecular reaction rate theory combined with potential energy surfaces derived at the ab initio G4//B3LYP/6-311++G(3df,3pd) level. The resulting rate constants are in good agreement with the available experimental information. Rate constant values for the reactions of CH₂Cl, CHCl₂, CHClBr, CH₂Br and CHBr₂ radicals with Br atoms are for a first time reported. Standard enthalpies of formation for the above and related molecules have been calculated.

Although correlation energy in an atom can be decomposed into different components such as inter- and intra-orbital pair-correlation energies (PCE), it is generally believed that the PCEs in different atoms cannot be the same. In this work, we find that when the correlation energy is defined as the difference between the exact ground-state energy and the unrestricted Hartree–Fock energy, the PCEs associated with the valence electrons of the atoms in the same row of the periodic table have the same values. For two specific orbitals, the inter-orbital correlation energy is the same between two electrons of parallel or anti-parallel spins.

Electrospray, essential in nanoparticle synthesis, biomedical diagnostics, and drug delivery, relies on onset field strength, the minimum electric field needed for liquid ejection. Nanoscale electrospray, with nanometer-sized nozzles, offers precise control and efficiency. This study uses molecular dynamics simulations to examine factors affecting onset field strength, such as pore geometry, solution environment, and surface properties. Findings show that surface properties can alter onset field strength by up to 50%, with enhanced hydrophilicity and negative surface charges reducing the required field strength. These insights are crucial for optimizing nanoscale electrospray in various applications.

The distinguishing features of Li-based ternary chalcogenides are their high thermal stability and adjustable optical characteristics. The present computational investigations focused on the complex interactions between the optical, thermal, and electronic properties of novel LiSmX₂ (X = S, Se) ternary chalcogenides. The calculated formation energy and cohesive energy values confirm the stability of these materials. The phonon dispersion results confirm their thermodynamic stability. The predicted spin-polarized band structure calculation signifies an indirect energy gap in both materials. The negative trend in the ε₁(ω), indicates that the response of these materials is more analogous to a metal within the given energy range. The intense peaks in the reflectivity spectra suggest that these materials can be employed as filter against UV radiations. Electronic band structures of LiSmS₂ and LiSmSe₂ may further improve the noticed linear rise in the thermal conductivity that helps electrons transmit heat more efficiently. Our present study may open the door to deeper investigations into these semiconductors’ optoelectronic and thermoelectric characteristics and potential use in optoelectronic and thermoelectric devices.

Allethrin and tetramethrin are both active ingredients in the production of insect spray. Being very toxic in nature, the inhalation of allethrin and tetramethrin causes various side effects in human beings. For the detection of allethrin and tetramethrin, the effectiveness of the base material phosphoaluminane is studied in the current work with the help of the density functional theory (DFT) calculations. The stability of phosphoaluminane is ensured with the support of formation energy and phonon band spectrum. The electronic properties of phosphoaluminane are systematically investigated using band structure and projected density of states (PDOS) maps. The obtained band gap value of phosphoaluminane is 1.716 eV, which confirms that the base material has semiconducting properties. The adsorption behaviour of target molecules allethrin and tetramethrin on phosphoaluminane are explored with prominent parameters including adsorption energy, Mulliken population analysis, and relative band gap changes. The adsorption energy range is recorded to be in the scope of −0.237 eV to −0.597 eV. From the results, it is clear that both allethrin and tetramethrin are physisorbed on phosphoaluminane sheets. Hence, novel phosphoaluminane nanosheets can be utilised as a sensing material for allethrin and tetramethrin.