Bound State Energy Research Articles

Tetraquarks: relativistic corrections and other issues

We discuss the effect of relativistic kinematics on the binding energy of multiquark states. For a given potential, the use of relativistic kinematics lowers the energy by a larger amount for the threshold made of two mesons than for a tetraquark, so that its binding is weakened. Some other issues associated with exotic hadrons are also briefly discussed.

Confinement effects of external fields and topological defect on hydrogen atom in a quantum-plasma environment

This study looks at the confinement effects of Aharonov-Bohm (AB) flux and magnetic fields, as well as topological defects in a quantum plasma, on the hydrogen atom. The joint effects show that the system is extremely attractive. Furthermore, as we've shown, the joint effect of the fields is greater than the sum of the individual effects, resulting in a significant change in the system's bound state energy. The magnetic field can be used as a control parameter or booster, whereas the topological defect and AB field are needed to hold the hydrogen atom in quantum plasmas at a low energy. The findings of our research may be extended to atomic structure and plasma collisions.

Quantifying the error propagation in microkinetic modeling of catalytic reactions with model-predicted binding energies

Energy prediction models, such as scaling relations, Brønsted–Evans–Polanyi relations and machine-learning prediction models, are widely employed to accelerate the calculations of energies of reaction intermediates and the rational design of catalysts. However, error propagation from predicted binding energies of reaction intermediates and transition states to the calculated reaction rates would result in the misidentification of optimal catalysts. In order to assess and quantify the error propagation in determining kinetic information for catalyst design, here we make energy error simulation based on DFT-calculated binding energies of reaction intermediates within the network of methane dry reforming reaction, then employ these simulated energies to microkinetic modeling. The results suggest that the microkinetic results would have different tolerance to the error indicators of predicted binding energy. Further detailed analyses show that binding energies with low variance are more likely to result in less significant error propagations during the calculation of reaction energy and activation energy, leading to more reliable kinetic information. Finally, several directions are discussed regarding the minimization of error propagation in microkinetic modeling based on predicted binding energies, and suggestions are provided for future studies.

Undamped Rabi oscillations due to polaron-emitter hybrid states in a nonlinear photonic waveguide coupled to emitters

The collective dynamics of two non-interacting two-level emitters, which are coupled to a structured wave guide that supports two-photon bound states, is investigated. Tuning the energy of the two emitters such that they are in resonance with the two-photon bound state energy band, we identify parameter regimes where the system displays fractional populations and essentially undamped Rabi oscillations. The Rabi oscillations, which have no analog in the single-emitter dynamics, are attributed to the existence of a collective polaron-like photonic state that is induced by the emitter-photon coupling. The full dynamics is reproduced by a two-state model, in which the photonic polaron interacts with the state $|e,e,\text{vac} \rangle$ (two emitters in their excited state and empty wave guide) through a Rabi coupling frequency that depends on the emitter separation. Our work demonstrates that emitter-photon coupling can lead to an all-to-all momentum space interaction between two-photon bound states and tunable non-Markovian dynamics, opening up a new direction for emitter arrays coupled to a waveguide.

The one-dimensional hydrogenic impurity states confined at one end of the InAs quantum well

ABSTRACT The one-dimensional (1-D) confined hydrogenic impurity states confined in the InAs quantum-well has been studied due to its wide application in manufacturing high-electron-mobility transistors in semiconductor physics. We calculate the energy levels and wave functions of this system using the linear variational method. Choosing the wave function of a particle confined in a 1-D infinitely deep quantum well as a basis set, we obtain the numerical solutions of the energy levels and wave functions of the hydrogenic impurity states confined at one end of the InAs quantum-well by solving the Hamiltonian matrix equation. It is found when the quantum well is very narrow, the eigen-energy approaches to the exact solution with a small number of basis set functions; whereas for a relatively wide quantum well, it is necessary to use a large number of basis set functions. The confinement effect of the quantum well on the energy level and binding energy of the hydrogenic impurity state has been studied in great detail. Although the linear variational method used in this work has only been applied to the hydrogenic impurity state confined in the quantum well, for the non-hydrogenic confined systems, this method is still applicable. Therefore, our work provides a new method to study the energy level structure of the impurity state confined in the external environment and has some practical applications in the fields of semiconductor physics, material science, etc.

Bound states in the continuum (BIC) protected by self-sustained potential barriers in a flat band system

In this work, we investigate the bound states in the continuum (BIC) of a one-dimensional spin-1 flat band system. It is found that, when the potential is sufficiently strong, there exists an effective attractive potential well surrounded by infinitely high self-sustained barriers. Consequently, there exist some BIC in the effective potential well. These bound states are protected by the infinitely high potential barriers, which could not decay into the continuum. Taking a long-ranged Coulomb potential and a short-ranged exponential potential as two examples, the bound state energies are obtained. For a Coulomb potential, there exists a series of critical potential strengths, near which the bound state energy can go to infinity. For a sufficiently strong exponential potential, there exist two different bound states with a same number of wave function nodes. The existence of BIC protected by the self-sustained potential barriers is quite a universal phenomenon in the flat band system under a strong potential. A necessary condition for the existence of BIC is that the maximum of potential is larger than two times band gap.

Eigensolution and Expectation Values of the Hulthen and Generalized Inverse Quadratic Yukawa Potential

Abstract: In this study, the Schrödinger equation was solved with a superposition of the Hulthen potential and generalized inverse quadratic Yukawa potential model using the Nikiforov-Uvarov (NU) method. For completeness, we also calculated the wave function. To validate our results, the numerical bound state energy eigenvalues was computed for various principal n and angular momentum l quantum numbers. With the aid of the Hellmann-Feynman theorem, the expressions for the expectation values of the square of inverse of position, r^(-2), inverse of position, r^(-1), kinetic energy, T ̂ and square of momentum, p ̂ are calculated. By adjusting the potential parameters, special cases of the potential were considered, resulting in Generalized Inverse Quadratic Yukawa potential, Hulthen potential, Coulomb potential, Kratzer potential, Inversely Quadratic Yukawa potential and Coulomb plus inverse square potential, respectively. Their energy eigenvalue expressions and numerical computations agreed with the literature. Keywords: Schrödinger equation, Hulthen potential (HP), Generalized inverse quadratic Yukawa potential (GIQYP), Nikiforov-Uvarov method. PACS: 03.65.−w, 03.65.Ca, 03.65.Ge.

Solutions of the Dirac equation with position-dependent mass for q-deformed Pöschl–Teller and Coulomb-like tensor potentials

We consider the Dirac equation with position-dependent mass for a q-deformed Pöschl–Teller potential plus a Coulomb-like tensor interaction in the limits of spin and pseudospin symmetries. Under the condition of spin symmetry, the bound state energy eigenvalue equation and the two radial components of the Dirac wave function in terms of the Jacobi polynomials are obtained approximately for an arbitrary shifted spin-orbit quantum number λκ = κ + H and for any value of the deformation parameter q ≥ 1. In the case of the pseudospin symmetry limit, there are no bound states. The Dirac equation describes a free physical system and the two components of the wave function are expressed in terms of the spherical Bessel functions.

CO2 chemisorption and dissociation on flat and stepped transition metal surfaces

As a promising and practical way to decrease CO2 emissions, the conversion of CO2 to value-added chemicals has received significant recent attention. The activation of CO2 on catalyst surfaces might proceed via a chemisorption state with a bent CO2 configuration, in which substrate electrons are transferred into the antibonding orbital of the CO2 adsorbate. Based on density functional theory calculations, we present an extensive survey of CO2 chemisorption and dissociation on flat and stepped surfaces of several transition metals. The binding energy of chemisorbed CO2 is closely correlated with the extent of electron transfer from the metal to CO2, as evidenced by a linear relationship found between the CO2 adsorption energy and its Bader charge. Transition state scaling (TSS) correlations between binding energies of transition states and binding energies of either initial or final states are found to exist for the dissociation of the chemisorbed CO2 on flat and stepped surfaces, which can be used to predict the efficacies of the catalysts. Our results show that defect sites at stepped surfaces have a strong influence on CO2 chemical activation and dissociation.

Interaction Potential for NaCs for Ultracold Scattering and Spectroscopy.

We obtain the interaction potential for NaCs by fitting to experiments on ultracold scattering and spectroscopy in optical tweezers. The central region of the potential has been accurately determined from Fourier transform spectroscopy at higher temperatures, so we focus on adjusting the long-range and short-range parts. We use coupled-channel calculations of binding energies and wave functions to understand the nature of the molecular states observed in ultracold spectroscopy and of the state that causes the Feshbach resonance used to create ultracold NaCs molecules. We elucidate the relationships between the experimental quantities and features of the interaction potential. We establish the combinations of experimental quantities that determine particular features of the potential. We find that the long-range dispersion coefficient C6 must be increased by about 0.9% to 3256(1)Eha06 to fit the experimental results. We use coupled-channel calculations on the final potential to predict bound-state energies and resonance positions.

Approximate solutions of the Schrödinger equation with Hulthén plus screened Kratzer Potential using the Nikiforov–Uvarov – functional analysis (NUFA) method: an application to diatomic molecules

The Schrödinger equation was solved for the Hulthén plus screened Kratzer Potential (HSKP) via the Nikiforov–Uvarov – functional analysis (NUFA) method. The bound-state energy and wave function for the HSKP were obtained in a closed form by applying the Greene–Aldrich approximation scheme to the inverse-square term. Using the resulting energy equation, we computed the energy spectra for 12 diatomic molecules (CuLi, TiH, VH, TiC, HCl, LiH, H2, ScH, CO, I2, N2, and NO) for various quantum states. To show the accuracy of our procedure, four special cases of the collective potential were obtained, and the results are in excellent agreement with the existing literature.

Spatially indirect excitons and exciton quasimolecules in nanosystems with double quantum dots

In mini-review, deals with the theory of exciton quasimolecules in a nanosystem consisting of double quantum dots of germanium synthesized in a silicon matrix. An exciton quasimolecule was formed as a result of the interaction of two spatially indirect excitons. It is shown that, depending on the distance D between the surfaces of the quantum dots, spatially indirect excitons and of exciton quasimolecules was formed in the nanosystem. The binding energy of the singlet ground state of the exciton quasimolecule has been gigantic exceeding the binding energy of the biexciton in a silicon single crystal by almost two orders of magnitude. The emergence of a band of localized electron states in the band gap of the silicon matrix was found. This band of localized electron states appeared as a result of the splitting of electron levels in the chain of germanium quantum dots.

Universal Josephson diode effect.

We propose a universal mechanism for the Josephson diode effect in short Josephson junctions. The proposed mechanism is due to finite Cooper pair momentum and is a manifestation of simultaneous breaking of inversion and time-reversal symmetries. The diode efficiency is up to 40%, which corresponds to an asymmetry between the critical currents in opposite directions Ic+/Ic− ≈ 230%. We show that this arises from both the Doppler shift of the Andreev bound state energies and the phase-independent asymmetric current from the continuum. Last, we propose a simple scheme for achieving finite-momentum pairing, which does not rely on spin-orbit coupling and thus greatly expands existing platforms for the observation of supercurrent diode effects.

Combination of LF‐NMR and BP‐ANN to monitor the moisture content of rice during hot‐air drying

AbstractIn this study, a rapid real‐time nondestructive method for detecting the moisture content of rice during hot‐air drying was investigated. Intelligent techniques of low‐field nuclear magnetic resonance (LF‐NMR) and back propagation artificial neural network (BP‐ANN) were applied to monitor the moisture content of rice. The effect of different hot‐air temperatures (35, 45, 55, and 65°C) on the moisture content and water migration within rice was studied. The results showed that the drying temperature promoted the diffusion and transfer of water within the rice, and was positively proportional to the drying rate. The binding energy of the different states of water within rice increased with the drying process, and the variation in relaxation time and peak area was consistent for each stage at different temperatures. In addition, the amount of LF‐NMR signals was used as an indicator to build a predictive model for the moisture content of rice during hot‐air drying. A BP‐ANN prediction model optimized by transfer function, training function and number of neurons was used to monitor the moisture content of rice using the amount of LF‐NMR signals of different states of water as input variables. The optimized neural network model had the excellent predictive ability with an MSE of 6.02 × 10−6 and R2 of 0.996. These results provide a reference for combining LF‐NMR and BP‐ANN in the application of intelligent online monitoring of hot‐air drying of rice.Practical ApplicationsThe monitoring of moisture content during hot‐air drying of rice is an essential parameter for optimizing the drying process. The combined approach of LF‐NMR and BP‐ANN for rapid real‐time nondestructive monitoring is well suited to hot‐air drying of rice, allowing for improved product quality and operational processes. In addition, the model developed in this study has the good predictive performance to meet the current industry and production needs, providing new research ideas and technical references for the optimization of the drying process of rice.

Study of thermomagnetic properties of the diatomic particle using hyperbolic function position dependent mass under the external hyperbolic magnetic and AB force

In this present work, we study the approximate solution of the Schrodinger equation with hyperbolic function position-dependent mass for a symmetrical Modified Poschl-Teller potential. We consider the system influenced by the external hyperbolic magnetic and Aharonov-Bohm (AB) forces. By using the Laplace transform method, the second-order differential equation of the Schrodinger equation is reduced to a first-order differential equation and so the eigenfunction and energy eigenvalues are obtained. The behavior of the bound state energy levels was demonstrated and analyzed using the computational method for various values of the potential parameter, mass parameter, external magnetic force, and AB force. Moreover, the thermomagnetic properties of the system were analyzed for H2, LiH, and HCl diatomic particles, involving the vibrational mean energy, vibrational free energy, vibrational entropy, specific heat capacity, magnetization, magnetic susceptibility, and persistent current.

Solutions of the Schrödinger equation with Hulthén-screened Kratzer potential: Application to Diatomic Molecules

In this study, the Schrödinger equation with the Hulthén plus screened Kratzer potentials (HSKP) are solved via the Nikiforov-Uvarov (NU) and the series expansion methods. We obtained the energy equation and the wave function in closed form with Greene-Aldrich approximation via the NU method. The series expansion method was also used to obtain the energy equation of HSKP. Three distinct cases were obtained from the combined potentials. The energy eigenvalues of HSKP for HCl, LiH, H2, and NO diatomic molecules were computed for various quantum states. To test the accuracy of our results, we computed the bound states energy of HCl and LiH, for a special case of Kratzer and screened Kratzer potentials, which are in excellent agreement with the report of other researchers.

Effect of Hydrogen Plasma Treatment on Atomic Layer Deposited Silicon Nitride Film

Changes in the thin film properties of SiNx deposited via atomic layer deposition using remote N2 plasma were investigated based on the frequency of adding a hydrogen (H2) plasma treatment step during the process. The deposition rate decreased from 0.36 to 0.32 A cycle−1 when compared to SiNx deposited through the conventional deposition process for a thin film that was subjected to H2 treatment processes every 10th cycle, every 5th cycle, and every single cycle of SiNx deposition compared to the deposition process without H2 plasma at a temperature of 400 °C. As the hydrogen treatment process increased beyond a 5:1 ratio, the hydrogen content in the thin film increased based on secondary ion mass spectroscopy analysis, and a change in binding energy state was shown via X-ray photoelectron spectroscopy. The thin film deposited using the hydrogen plasma treatment process at a ratio of 10:1 showed similar characteristics to the SiNx thin film deposited through the conventional atomic layer deposition process and showed excellent etch resistance without an increase in the etch rate. The step coverage characteristics were increased by 16% compared to the deposition process without a H2 plasma treatment process.

Temperature effect of strong-coupling polaron in RbCl quantum wells with double asymmetric confined potentials

In this study, the ground state properties of strong-coupling polaron in RbCl quantum wells (QWs) by using double asymmetric confined potential were theoretically investigated based on effective mass approximation. Ground state binding energy (GSBE), ground state energy (GSE), vibrational frequency (VF), and mean LO phonon number (MLOPN) were obtained as functions of asymmetric confinement potential parameters in QWs by using the unitary transformation method and linear combination operator. GSBE, GSE, VF and MLOPN were found to be increasing functions of asymmetric semi-exponential confinement potential (ASECP) parameter [Formula: see text] and decreasing functions of parameter [Formula: see text]. GSE was rapidly increased with the increase of confinement strength. GSBE, GSE, VF and MLOPN increase as the increasing (decreasing) of anisotropic parabolic confinement potential strength (confinement length). In addition, the temperature effect was evaluated by using quantum statistical theory. With the increase of temperature, GSE and GSBE decreased while VF and MNLOP increased.

A‐Site Diamine Cation Anchoring Enables Efficient Charge Transfer and Suppressed Ion Migration in Bi‐Based Hybrid Perovskite Single Crystals

AbstractDue to the large distance or weak electronic conjugation between adjacent Bi‐I octahedrons, the charge transport in the low‐dimensional bismuth‐based hybrid perovskites is impeded and thus hinders their future developments. In this work, A‐site cation engineering by monoamine BZA (benzylamine) and diamine 3‐AMP (3‐(aminomethyl)pyridine) has been demonstrated as an efficient strategy to regulate the corresponding activation energy of ionic migration and carrier transport capacity. Given the higher polarity of 3‐AMP than BZA, producing a more efficient dielectric screening effect, it gives rise to obtaining the small exciton binding energy (50 meV) and low defect states (3.53×109 cm−3). The reduced distance of adjacent Bi‐I octahedrons by the bilateral anchoring of the 3‐AMP2+ diamine cation enhances both electronic conjugation and charge transport performance. Therefore, the photodetector for (3‐AMP)BiI5 SC shows a 243‐fold increase in on/off ratio compared with the (BZA)3BiI6 SC.

A-Site Diamine Cation Anchoring Enables Efficient Charge Transfer and Suppressed Ion Migration in Bi-Based Hybrid Perovskite Single Crystals.

Due to the large distance or weak electronic conjugation between adjacent Bi-I octahedrons, the charge transport in the low-dimensional bismuth-based hybrid perovskites is impeded and thus hinders their future developments. In this work, A-site cation engineering by monoamine BZA (benzylamine) and diamine 3-AMP (3-(aminomethyl)pyridine) has been demonstrated as an efficient strategy to regulate the corresponding activation energy of ionic migration and carrier transport capacity. Given the higher polarity of 3-AMP than BZA, producing a more efficient dielectric screening effect, it gives rise to obtaining the small exciton binding energy (50 meV) and low defect states (3.53×109 cm-3 ). The reduced distance of adjacent Bi-I octahedrons by the bilateral anchoring of the 3-AMP2+ diamine cation enhances both electronic conjugation and charge transport performance. Therefore, the photodetector for (3-AMP)BiI5 SC shows a 243-fold increase in on/off ratio compared with the (BZA)3 BiI6 SC.