Laser-induced nuclear phenomena are progressing rapidly with significant advancements in the field of controlled nuclear reactions. This study introduces a novel cross-disciplinary extension of laser-matter interaction theories to nuclear decay processes, opening up possibilities for controlled manipulation of nuclear lifetimes using high-intensity laser environments. We have investigated X-ray laser-assisted a-particle tunneling in even-even and doubly-odd heavy radioactive nuclei using a Floquet-Volkoff (FV) formalism for multiphoton-induced a-decay. This approach is grounded in a microscopic phenomenological framework that incorporates the Skyrme force model of a-nucleus potential within the Wentzel-Kramers-Brillouin (WKB) approximation. Our results demonstrate that emission of the a-particle is influenced by multiphoton absorption to a considerable extent. The nuclei with larger effective charge (Zeff) and smaller disintegration energies (Qa-value) are found to be more sensitive to such perturbations. It is found that the logarithmic values of relative enhancement in the penetration probabilities (log10 Delta Prel-values) can be effectively parameterized as a function of Zeff. Furthermore, the relative enhancement in penetration probability (Delta Prel) can be directly related to the change in a-decay half-lives i.e. Delta Tel-values.

Major advances in molecular diagnostics have fueled the search for nanosensors that can detect anomalies in their early stages of development. In this research work, we have investigated a tetracene molecule bridged between gold electrodes in a device configured for sensor application in medical diagnostics. Density functional theory (DFT) and non-equilibrium Green’s (NEGF) functions have been utilized to study the feasibility of tetracene molecular junctions for detecting the presence of arsenic and tracing its concentration. In this context, transmission spectra, molecular-projected self-consistent Hamiltonian (MPSH), current–voltage curve, conductance trends, and HOMO–LUMO gap (HLG) at different operating voltages are determined. Notably, during exposure of the molecular junction to varying concentrations of arsenic, substantial changes are detected in the electron transport properties. Both the conductance and current of the molecular junction escalates with the increase in impurity of the arsenic atoms, thus proving that tetracene is a suitable candidate to be explored as a nanosensor.

By applying non-equilibrium green’s function (NEGF) formalism combined with density functional theory (DFT), this study aims to investigate and compare the electron transport properties of tetracene molecules anchored with C20, C24 and C28 fullerene molecules. The results indicate that tetracene molecule exhibits metallic behaviour with C20 anchors, whereas C24 and C28 fullerenes, respectively, show semi-metallic and non-metallic nature. Various attributes such as transmission spectrum, density of states (DOS), molecular projected self-consistent Hamiltonian (MPSH) eigen states, conductance and current characteristics conclude that shifting of the molecular orbitals with variations in the bias voltage determines the current spectrum. The nonlinearity in the I–V curve and troughs in the G–V curve are attributed to the transitions seen in the active molecular orbitals, resulting in a variation in the HOMO–LUMO gap. Further, a multifunctional behaviour showing a clear negative differential resistance region with peak-to-valley current ratio of 1.70 and rectifying performance with a rectification ratio of 1.45 in the case of C20–tetracene–C20 molecular junction is observed. These results will pave a new road map for developing versatile molecular devices with targeted properties.

To ensure safety and security from the insects, it has become essential to develop the use of insect repellent agents that can be applied on the clothes in the form of fabric finishing. Unlike synthetic insect repellent, natural insect repellent does not have any disadvantages. In this article, the flowers of Tagetes patula commonly known as “Marigold” are chosen as natural insect repellent. Various extracts (aqueous, methanol, ethyl acetate and n-heptane) of marigold flowers have been prepared and investigated. It is found that the methanolic extract is most satisfactory amongst all for both the bamboo and wool fabric as far as dye exhaustion and color yields are concerned which has been proved by K/S values, D65 (10 deg observer) values, TLC analysis for compound determination, washing fastness record for bond formation analysis and insect repellent property. This study, therefore, suggests that extract of Tagetes patula flowers can be used as a colorant as well as an insect repellent for wool and bamboo fabric.

A five-level microwave-driven X-type scheme is used to study the influence of various field parameters on the absorption and nonlinear dispersion of probe light. In the proposed system, the cross-Kerr nonlinearity can be enhanced by optimum setting of the field strength and detunings. Our calculation reveals that the amplitude and position of the cross-Kerr peaks can be manipulated by tuning the microwave Rabi frequency and relative phase parameter. This proposed scheme has potential applications in the realm of multichannel quantum gates.

In this proposed work, we report Co-Ti doped Strontium-lanthanum M−type hexaferrites with general chemical formula, Sr0.85La0.15(CoTi)0.5Fe11O19 and Sr0.85La0.15(CoTi)0.75Fe10.5O19 prepared by citrate auto-combustion method. Complex permittivity, complex permeability and microwave absorptive properties of fabricated ferrite compositions were analysed in 12.4 to 18 GHz frequency range (Ku-Band). The XRD (X-ray diffraction) pattern of Co-Ti substituted compositions show single-phase M−type hexagonal ferrite indicating this co-substitution maintained the crystal phase structure. The grain diameter (average) decreased from 587 nm to 290 nm and 415 nm to 318 nm for ferrite samples with composition x  = 0.50 and x  = 0.75 respectively after 20 hours of ball-milling. The reflection loss (RL) exhibited the absorption bandwidth of more than 90 % (−10 dB) of value 2.41 GHz and 1.2 GHz for fabricated ferrites with chemical composition Sr0.85La0.15(CoTi)0.5Fe11O19 and Sr0.85La0.15(CoTi)0.75Fe10.5O19 respectively.. Both dielectric loss tangent and magnetic loss tangent contributed to enhance total loss tangent which represents microwave absorbing properties of the prepared ferrite samples. Reflection coefficient (S11) values for open circuit method also shows absorption bandwidth (−10 dB) of more than 90 % for these ferrites. Double layer electromagnetic absorber was simulated and observed improved reflection loss and absorption bandwidth. Therefore, these suggested ferrite samples have potential to be used as electromagnetic wave absorbing material of both single and double layer at higher frequency range.

The nonlinear Schrödinger equation (NLSE) describes various types of physical systems such as water waves, nonlinear optics, plasma Physics. In optics, NLSE describes a wide range of non-linearity effects in fiber optics. The solution to the above equation might be examined in order to investigate these consequences. Differential configurational entropy (DCE) is used to analyze the dark similariton solution in this specific situation of NLSE with bright and dark similariton solutions. DCE provides us with the measure of information required to examine stability for various physical systems and to characterize a systems spatial profile using the Fourier transform. It is show that even for the same solitonic solution of the NLS equation, the variations in the spatial shape is induced by different choices of the relevant parameter α. The global minima of the DCE correspond to the saturation of the breadth of dark solitons. While dark similariton waves propagate through waveguides, such low entropic values result in minimum dispersion of momentum modes, and this should be taken into consideration while designing the waveguides.

By applying NEGF formalism combined with DFT, the electron transport properties of tetracene molecule stringed to asymmetric electrodes have been investigated. To induce asymmetry in the molecular junctions, the left electrode is kept as Au while the right electrode is varied with Ag, Cu and Pt in each case. A comparison between the rectification trends of the asymmetrical junctions is done by the analysis of current–voltage characteristics, transmission spectra and MPSH. The results depict that the rectification behaviour can be escalated by using dissimilar metallic electrodes. It is found that the tetracene molecule exhibits significant rectification behaviour with a peak rectification ratio of 3.41 when coupled with gold and copper electrode combination. In addition, NDR behaviour within a certain bias voltage is observed in all the molecular junctions with the highest PVCR of 1.78 in Au-Tetracene-Ag molecular junction. Our findings highlight that changing the electrode material would efficiently improve the characteristics of a metal–molecule-metal junction and can provide a guide for the design of functional molecular devices.

By employing both perturbative and nonperturbative techniques, we study the small and large amplitude stationary formations of ion acoustic waves in plasma containing relativistically degenerate electrons. We derive the expressions for double layers and solitons following Sagdeev's pseudopotential approach. Such a stationary structure becomes interesting around the critical density. To study the nonlinear formations around the critical region, we obtained the modified Korteweg-de Vries (m-KdV) equation and analyzed its parametric dependence. We have obtained kink and Gardner solitons and studied the parametric dependence. In addition, we have studied the wave-wave interaction, and the subsequent phase shifts have been studied with reference to various parameters. These are a precursor to the attainment of criticality in the problem. These findings will help in laser-plasma interactions regarding the relaxation time and the energy context. Short-pulse lasers and their applicability in various plasma applications may be predicted from these findings.

A method of generating THz radiation by nonlinear mixing of lasers obliquely incident on a finite slab of overdense plasma is formulated analytically. The incoming laser beam exerted a ponderomotive force on free electrons, which started oscillating at a frequency equal to the frequency difference of two laser beams. This results in a nonlinear current leading to THz radiation generation at the reflection as well as at the transmission side of the plasma slab. We have seen the effect of incident angle on the amplitudes of reflected and transmitted amplitudes of generated THz radiation. It is observed that the thickness of the slab and plasma density are the contributing parameters for the intensity of THz radiation generation.

Density functional theory in combination with non-equilibrium Green's function is employed to study the electron transport properties of tetracene-based molecular junctions formed with silver, gold, copper and platinum electrodes. The physical origin of the IV curves is discussed by analyzing their density of states, molecular projected self-consistent Hamiltonian, transmission spectra, conductance trends and HOMO-LUMO gap at different operating voltages. The results indicate that till a low bias voltage of 1.4 V, the tetracene molecule shows metallic behavior with silver and copper electrodes while semi-metallic and non-metallic nature with gold and platinum electrodes respectively is observed. The zero bias conductance is found to be greatest for Ag followed by Cu and Au with the least in Pt. Furthermore, it is worth mentioning that negative differential resistance feature is observed in molecular junctions with all the electrodes except Pt, with the highest peak-to-valley current ratio of 1.283 found in Ag-Tetracene-Ag molecular junction.

In this present research, comparative analysis of dielectric and electrical properties of M−type lanthanum-strontium (La-Sr) hexaferrites substituted with Co-Zr, Mn-Zr and Ni-Zr with chemical formulae: Sr0.85La0.15(CoZr)xFe12-2xO19, Sr0.85La0.15(MnZr)xFe12-2xO19 and Sr0.85La0.15(NiZr)xFe12-2xO19 (where x is 0.00 to 1.00 with ratio of 0.25) respectively have been investigated in 1 kHz to 1 MHz frequency range. The dielectric constant and loss tangent shows decreasing trend with frequency and AC conductivity shows increasing trend with it. Dielectric constant, tangent loss and AC conductivity are increased with increase in substitution of Co-Zr and Mn-Zr doped La-Sr ferrites but these parameters shows opposite trend for Ni-Zr doped La-Sr hexaferrites. The higher electron exchange between ferrous cations (Fe2+) and ferric (Fe3+) cations are responsible for the higher polarization in ferrites. These newly synthesized ferrites have great potential for microwave absorbing material and microwave components.

The thermoelectric properties of armchair silicene nanoribbons embedded with pores of varying morphology are studied using atomistic simulation of electron and phonon transport. The results show that the phonon thermal transport is significantly reduced by the introduction of nanopores. Although the Seebeck coefficient exhibits an oscillating behavior with the pore size, the improved values of conductance are able to improve the power factor substantially which leads to enhancement of thermoelectric performance. Moreover, it is observed that the enhancement of thermoelectric figure of merit can be effectively tuned by the optimum choice of pore shape which is found to be dependent upon the pore dimension. In addition, the effect of variation in temperature on the thermoelectric performance has been studied.

Non-equilibrium Green’s function (NEGF) and density functional theory (DFT) calculations are used to explore the impact of doping on the electron transport properties in a single tetracene molecule linked to gold electrodes using isocyanide anchoring groups. Boron (B) and Nitrogen (N) atoms are used for doping and co-doping (BN) of the carbon atoms placed at the edge of the tetracene molecule. It was found that the chemical doping of tetracene molecules mainly impacts the rectification trends compared to non-doped molecules. Our findings indicate that B doping significantly improves the rectification ratio compared to other dopants because of a greater difference between the current values under positive and negative biases as a result of asymmetric I-V characteristics. These inferences have also been assessed in terms of MPSH and transmission spectra. In addition, novel characteristic of negative differential resistance (NDR) is attained in single dopant molecular junctions.

In this work, we investigated the impact of Mn substitution on the morphological, structural, and optical properties of barium strontium titanate (BST) with the formula Ba0.92Sr0.08Ti1−xMnxO3 (x = 0.00, 0.10, 0.20) fabricated using the solid-state reaction technique. The morphological and structural properties were studied using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The optical properties of the samples were analyzed using photoluminescence (PL), Fourier transform infrared (FTIR), and Raman spectroscopy. SEM micrographs displayed nearly spherical grains. The phase formation, lattice structure, crystallite size (D), strain (ε), and dislocation density (δ) of the Mn-doped BST ceramics were examined from the recorded XRD patterns using the Scherrer and Williamson–Hall (W–H) models, which showed that the crystallite size increased and the lattice strain and dislocation density decreased with increasing doping concentrations. FTIR results for the pristine sample of BST revealed that the absorption peak at a wavenumber of 470 cm−1 was shifted to 1250 cm−1 for Mn-doped BST concentrations. The Raman results indicated that the number of modes decreased with the increase in the Mn2+ concentrations. PL spectra showed an emission band centered at 60–659 nm, indicating redshift behavior. The analysis using XRD, SEM, FTIR, and Raman spectroscopy revealed that the concentration x = 0.20 is appropriate for use in microwave devices and other electro-optical applications.

ContextThis study aims to tune the transport properties of tetracene single-molecule junctions with the proper choice and placement of side and anchoring groups. For the operationalization of the molecule that was anchored with thiol or isocyanide groups, two different side groups, amine and nitro, in two different positions, were taken into consideration. For unperturbed tetracene molecule, a prominent negative differential resistance (NDR) feature at 1.8 V was observed with the isocyanide anchoring group while the thiol anchoring group exhibits a plateau region over a bias voltage of 2.2 to 3.2 V. At a bias voltage that is dependent on the chemical or structural change of side or anchoring groups, NDR feature of varying degree was seen in all configurations. Results show that the current flowing through the thiol-anchored molecule perturbed with the amine group at S' position is relatively larger than other configurations because of the smaller HOMO-LUMO gap and broader transmission peaks resulting in a peak to valley current ratio (PVCR) of 1.22. In addition, multiple NDR regions were realized in nitro-perturbed isocyanide-anchored molecule at S position. These results suggest their promising applications in switches, logic cells, and storage devices.MethodsThe modeling and simulation of side-group mediated anchored tetracene molecule through two electrodic systems were studied using density functional theory (DFT) combined with non-equilibrium Green's function (NEGF) in Virtual NanoLab-AtomistixToolkit (ATK). The electron transport properties were calculated using Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) exchange-correlation function. To optimize computing time, gold electrodes were single zeta polarized whereas the molecule, anchor groups, and side groups were double zeta polarized.

This study describes the relativistic q-Gaussian laser beam's stimulated Raman scattering (SRS) in an unmagnetized plasma. Moreover, the influence of the pump laser's relativistic self-focusing on the SRS process has been investigated. Using variational theory, we derived analytical solutions to the coupled nonlinear wave equations describing the pump, EPW, and scattered waves. The resulting equations were numerically solved to see the impacts of laser and plasma characteristics on the dynamics of the pump beam and its influence on the power of scattered waves. The power of the scattered wave was observed to be significantly altered via the self-focusing action of the pump beam, where when the effect of self-focus increases, it leads to an increase in the effect of stimulated Raman scattering. The stimulated Raman scattering yield is investigated based on the laser beam's and plasma's intensity. The main finding is that as q increases, the SRS yield increases, and as the intensity of the laser beam and plasma density increase, the SRS yield also increases. The scattering of the self-focused beam takes place at a greater distance than the beam of the pump, due to the relatively diminished level of scattered power. The value of the integrated reflection increases with the increase of q and the growth rate.

This study aims to investigate the electronic transport properties of tetracene molecule connected to gold (Au) electrodes with asymmetric anchoring groups. More specifically, we investigate the effect of asymmetric electrode coupling on the rectification ratio of tetracene-based molecular device. To introduce coupling asymmetry in these junctions, one end of the tetracene molecule is terminated with thiol (−SH) or isocyanide (−NC) while the other end with amine (−NH2) or nitro (−NO2) anchoring group. The results indicate that the electronic transport behavior is affected by the nature of molecule-electrode coupling, and the rectification ratio can be modulated by a proper choice of the anchoring groups. We reveal that the tetracene molecule when connected with isocyanide and amine combination exhibits remarkable rectifying performance (with a rectification ratio of 74) in contrast with other configurations. Furthermore, a prominent negative differential resistance (NDR) feature is observed when the molecule is connected with thiol as one of the anchors. Our present findings with excellent rectifying performance and negative differential resistance pave a new roadmap for designing multifunctional molecular devices. By applying non-equilibrium Green’s function (NEGF) formalism combined with density functional theory (DFT) Atomistic Tool Kit software package, the electronic transport properties of tetracene molecule connected to gold electrodes with asymmetric anchoring groups have been investigated. The calculations were performed using the Perdew-Burke-Ernzerhof (PBE) parameterization of DFT within generalized gradient approximation (GGA) exchange-correlation functional. To improve calculation precision and save computational efforts, the molecule and anchor groups were double-ζ (DZ) polarized, while single-ζ (SZ) polarized basis set was used for gold electrodes.

Terahertz spoof plasmon propagation in a vacuum region sandwiched by a planar and corrugated parallel metal plate has been analytically and numerically investigated. Metallic corrugations in the form of long rectangular grooves in transverse direction support confined surface plasma wave propagation in the THz regime. The parallel metal surface in close proximity ensures the propagation of spoof plasmons in a highly confined manner. A theoretical dispersion relation is obtained corresponding to the waveguide design using the effective medium approximation method which confirms plasmonic behavior. Further, the technique of finite difference time domain method is used to study the terahertz mode propagation along the waveguide. The attenuation coefficient and propagation length are calculated to understand the guided wave capability of the waveguide configuration. This study is helpful to analytically understand the role of corrugations in parallel plate configuration in guiding the terahertz modes and hence can be significant in designing plasmonic devices for terahertz photonics