Total Interaction Potential Research Articles

The study of angular momentum on the fusion of [formula omitted]Si+[formula omitted]Si, using SEDF in semiclassical extended Thomas-Fermi approach

The total fusion cross-sections are calculated for energies both above and below the potential barrier by using the properties of the interaction potential in Hill-Wheeler approximation for a positive Q-value system 1428Si+1428Si. The Coulomb and centrifugal parts of the potentials are added directly to the nuclear proximity potential to calculate the total interaction potential, where nuclear proximity potential is obtained in semiclassical extended Thomas-Fermi approach of Skyrme energy density formalism for Skyrme SIV parametrization. The angular momentum spectrum of total cross sections is obtained and calculated by using angular momentum dependent properties of the total interaction potential. The properties of total interaction potential, which are usually treated as independent of angular momentum, i.e. barrier height, barrier position and its width are calculated and found to depend sharply on the angular momentum value at a fixed center of mass energy. It effect the fusion cross-section sufficiently above the barrier energy. However at energies below the barrier energy the addition of large angular momentum values have negligible effects on fusion cross-section. Further, the maximum in fusion cross-section is observed at a particular value of angular momentum, which is not equal to the maximum value of angular momentum.

Formation and dissociation of CO2 hydrates in porous media in the presence of clay suspensions

CO2 storage in marine sediments in the form of solid hydrates with high storage capacity and stability is a promising approach for the control of greenhouse gas pollution. Specifically, clay is much abundant in marine minerals, and multiple forces exist between fine clay particles suspended in seawater, significantly affecting the hydrate formation and dissociation behavior. This study investigates the phase transition performance of CO2 hydrates with or without montmorillonite and illite particles using low-field nuclear magnetic resonance. According to the DLVO theory, the total interaction potential between the montmorillonite particles reached 358 kbT, with that between illite particles being only 43 kbT. It was found that water in large pores was preferentially consumed during hydrate formation, with clay particles significantly promoting the conversion of water into hydrate. In seawater-montmorillonite and seawater-illite solutions, a higher number of water molecules was detected in the small and medium pores, respectively. Notably, the initial pore structure changed upon hydrate dissociation, with more medium pores formed. This effect was enhanced in the seawater-montmorillonite solutions and weakened in seawater-illite solutions. The findings could further clarify the formation and dissociation kinetics of CO2 hydrates in the presence of clay particles, as well as the geological structure evolution and safety of CO2 hydrate storage under the seafloor.

Multiphysics Modeling of Low-Intensity Pulsed Ultrasound Induced Chemotherapeutic Drug Release from the Surface of Gold Nanoparticles.

Currently, no numerical model for low-intensity pulsed ultrasound (LIPUS)-triggered anticancer drug release from gold nanoparticle (GNP) drug carriers exists in the literature. In this work, LIPUS-induced doxorubicin (DOX) release from GNPs was achieved in an ex vivo tissue model. Transmission electronic microscopy (TEM) imaging was performed before and after LIPUS exposure, and significant aggregation of the GNPs was observed upon DOX release. Subsequently, GNP surface potential was determined before and after LIPUS-induced DOX release, using a Zetasizer. A numerical model was then created to predict GNP aggregation, and the subsequent DOX release, via combining a thermal field simulation by solving the bioheat transfer equation (in COMSOL) and the Derjaguin, Landau, Verwey, and Overbeek (DLVO) total interaction potential (in MATLAB). The DLVO model was applied to the colloidal DOX-loaded GNPs by summing the attractive van der Waals and electrostatic repulsion interaction potentials for any given GNP pair. DLVO total interaction potential was found before and after LIPUS exposure, and an energy barrier for aggregation was determined. The DLVO interaction potential peak amplitude was found to drop from 1.36 kBT to 0.24 kBT after LIPUS exposure, translating to an 82.4% decrease in peak amplitude value. It was concluded that the interaction potential energy threshold for GNP aggregation (and, as a result, DOX release) was equal to 0.24 kBT.

Towards a total interaction potential from experimental transferred electron density

Towards a total interaction potential from experimental transferred electron density

Systematic study of two-proton radioactivity within various versions of proximity formalisms

In this work, we study the two-proton (2p) radioactivity half-lives for nuclei near or beyond the proton drip line within the Coulomb and proximity potential model (CPPM). We investigate the 28 versions of proximity potential formalisms, which were proposed for heavy-ion fusion reactions, heavy-ion elastic scattering, ternary fission and other applications. The results indicate that BW91 and Bass77 are inappropriate for handling 2p radioactivity since the classical turning point r in cannot be obtained for the depth of the total interaction potential between the released two protons and daughter nucleus being greater than the 2p radioactivity released energy. Among the other 26 proximity potential formalisms, the one proposed by Royer et al in 1984 denoted as Prox.77-8 is the best version with the lowest rms deviations between experimental data and relevant theoretical results. It is worth mentioning that the calculations of Coulomb and Proximity Potential Model for Deformed Nuclei (2021 PRC 104, 064 613) has least standard deviation (σ = 0.592) compared with present model and other models/formulae. Furthermore, we use CPPM with Prox.77-8 to predict the 2p radioactivity half-lives of 35 potential candidates whose 2p radioactivity is energetically allowed or observed but not yet quantified in NUBASE2020. The predicted results are consistent with previous theoretical models such as the unified fission model (UFM), generalized liquid drop model (GLDM) and effective liquid drop model (ELDM).

Accelerated causal Green's function molecular dynamics

A Green's function formalism has been applied to solve the equations of motion in classical molecular dynamics simulations. This formalism enables larger time scales to be probed for vibration processes in carbon nanomaterials. In causal Green's function molecular dynamics (CGFMD), the total interaction potential is expanded up to the quadratic terms, which enables an exact solution of the equations of motion to be obtained for problems within the harmonic approximation, reasonable energy conservation, and fast temporal convergence. Differently from conventional integration algorithms in molecular dynamics, CGFMD performs matrix multiplications and diagonalizations within its main loop, which make its computational cost high and, therefore, has limited its use. In this work, we propose a method to accelerate CGFMD simulations by treating the full system of N atoms as a collection of N smaller systems of size n. Diagonalization is performed for smaller nd×nd dynamical matrices rather than the full Nd×Nd matrix (d=1,2, or 3). The eigenvalues and eigenvectors are then used in the CGFMD equations to update the atomic positions and velocities. We applied the method for one-dimensional lattices of oscillators and have found that the method rapidly converges to the exact solution as n increases. The computational time of the proposed method scales linearly with N, providing a considerable gain with respect to the O(N3) full diagonalization. The method also exhibits better accuracy and energy conservation than the velocity-Verlet algorithm. An OpenMP parallel version has been implemented and tests indicate a speedup of 14× for N= 50000 in affordable computers. Our findings indicate that CGFMD can be an alternative, competitive integration technique for molecular dynamics simulations.

Manifestation of deformation and nonlocality in α and cluster decay

It is common to study the strong decay of a heavy nucleus as a tunneling phenomenon where the $\alpha$ ($^4$He) or a light nuclear cluster tunnels through the Coulomb barrier formed by its interaction with the heavier daughter nucleus. The position and width of the Coulomb barrier are determined by the total interaction potential between the two daughter nuclei. We examine the effects of including nonlocality and deformation in the interaction potential by calculating the half-lives, $t_{1/2}$, and thereby phenomenological preformation factors of several nuclei which have the possibility of decaying by emitting either an $\alpha$ or a light nuclear cluster. The effect of deformation manifests itself by a decrease in $t_{1/2}$ for all the decays studied. The effect of nonlocality is studied within two different models of the nuclear potential: the energy-independent but angular momentum ($l$) dependent Mumbai (M) potential and the energy-dependent Perey-Buck (PB) potential. The nonlocal nuclear interaction leads to a decrease in all half-lives studied. Though the decrease is larger due to the Perey-Buck potential, half-lives evaluated using the Mumbai potential show a strong sensitivity to the $l$ value in the decay. This feature of the $\alpha$ and cluster decay half-lives can provide a complementary tool in addition to scattering data which are more commonly used to fix the parameters of a nonlocal potential in literature.

Ionic Interactions at the Crude Oil-Brine-Rock Interfaces Using Different Surface Complexation Models and DLVO Theory: Application to Carbonate Wettability.

The impact of ionic association with the carbonate surface and its influence toward carbonate wettability remains unclear and is an important topic of interest in the current literature. In this work, a triple layer model (TLM) approach was used to capture the electrokinetic interactions at both calcite–brine and oil–brine interfaces. The developed TLM was assembled against measured ζ-potential values from the literature, successfully capturing the trends and closely matching the ζ-potential magnitudes. The developed TLM was compared to a diffused layer model (DLM) presented in previous works, with the DLM showing a better match to the ζ-potential values for seawater brine solutions. The ζ-potential values predicted from both surface complexation models (SCMs) were used to calculate the total interaction energy (or potential) based on the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory. It was observed that low Mg2+ and high SO42– concentrations in modified composition brine (MCB) made the calcite–brine interface more negative. However, at the oil–brine interface, low Mg2+ made the oil–brine interface more negative but high SO42– concentrations slightly shifted the oil–brine ζ-potential toward negative. At the crude oil–brine–rock (COBR) interfaces, low Mg2+ and high SO42– concentrations in the MCB were observed to generate a greater repulsive interaction energy, which could trigger carbonate wettability alteration toward water wetness. The absolute sum of the ζ-potential at both interfaces was observed to be correlated to the total interaction potential at a 0.25 nm separating distance. Thus, an increase in the absolute sum of the ζ-potentials would generate a greater repulsive interaction potential and trigger wettability alteration. Therefore, these SCMs can be applied to design modified composition brine capable of triggering a repulsive interaction energy to alter carbonate wettability toward water wetness.

Electromagnetic description of the interaction between talcum and the rough surface of a composite material

We study the effects of surface roughness and composition of NixFe1−x material on a talc particle-surface adhesion. Experimental results are astonishingly consistent with our theoretical simulation that the lowest value of the total interaction potential between talcum and the material is proportional to the probability of contamination. The AFM result s’ tendency corresponds to surface force s’ simulation. Finally, we discover the electromagnetic description of the interaction between talcum and the rough surface at the lowest potential is proportional to the sum of each side’s square that involves dielectric constants and surface’s roughness.

Single file diffusion meets Feynman path integral

The path-integral representation of the Smoluchowski equation is exploited to explore the stochastic dynamics of a tagged Brownian particle within an interacting system where hydrodynamic effects are neglected. In particular, this formalism is applied to a particle system confined to a one-dimensional infinite line aiming to investigate the single-file diffusion phenomenon in this scenario. In particular, the path-integral method is contrasted against the standard many-particle Langevin equation for a system of interacting Brownian particles in a harmonic chain model, exhibiting excellent agreement; in this case of study a formula defined on the whole time-scale for the mean-square displacement, in the thermodynamic limit, is found for the tracer particle in terms of Bessel functions, recovering also the single-file regime. Additionally, a Brownian particle system with paramagnetic interactions is considered near crystallization where the total interaction potential is roughly a harmonic potential. Taking advantage of the path-integral formalism a simple perturbation treatment is carried out to investigate the single file diffusion behaviour when temperature is increased from the crystal phase, where we also validate our findings using Brownian dynamics simulation.

Systematic study of two-proton radioactivity with a screened electrostatic barrier * *Supported in part by the National Natural Science Foundation of China (11205083, 11505100, 11705055), the Construct Program of the Key Discipline in Hunan Province, the Research Foundation of Education Bureau of Hunan Province, China (18A237), the Natural Science Foundation of Hunan Province, China (2018JJ3324), the Innovation Group of Nuclear

In this study, a phenomenological model is proposed based on Wentzel-Kramers-Brillouin (WKB) theory and applied to investigate the two-proton ( ) radioactive half-lives of nuclei near or beyond the proton drip line. The total diproton-daughter nucleus interaction potential is composed of the Hulthen-type electrostatic term and the centrifugal term. The calculated radioactive half-lives can accurately reproduce the existing 10 experimental datasets of five true radioactive nuclei with σ = 0.736. In addition, we extend this model to predict the half-lives of possible radioactive nuclei whose radioactivity is energetically allowed or observed but not yet quantified in NUBASE2016. The predicted results are in agreement with those obtained using the Gamow-like model, generalized liquid drop model, Sreeja formula, and Liu formula.

Particle-substrate interactions in the laser deposition process

We theoretically study particle-substrate interactions under laser irradiation. Van der Waals, electrostatic double layer and a laser induced dipole in the nanoparticle and an image dipole in the substrate were considered to be the major components of the total interaction potential. It was shown that laser-induced attractive potential energy between the particle and substrate reduces the potential barrier which increases the probability for metal nanoparticles to be deposited onto the substrate.

Systematic study of proton emission half-lives within the two-potential approach with Skyrme-Hartree-Fock

In this work we systematically study the proton emission half-lives of 53≤Z≤83 nuclei within the two-potential approach with Skyrme-Hartree-Fock. At first, we use this model to study the proton emission half-lives of 32 spherical nuclei. The total proton-daughter nuclei interaction potential includes: the microscopic nuclear potential calculated by the spherical Hartree-Fock self-consistent equation with the Skyrme effective interaction of SLy4, SkC and SkD, the Coulomb potential obtained under the assumption of a uniformly charged sphere and the Langer modified centrifugal potential. The calculations can reproduce the experimental data well. And then, we extend this model to the deformed cases and compare it with other models. Meanwhile, we discuss the relationship between the theoretical half-lives of parent nuclei 113Cs, 117La, 121Pr, 135Tb and 141Ho and corresponding l values taken away by emitted proton. A set of these parent nuclei reference values of l are given to calculate the theoretical half-lives which are more in line with experimental data. At last, we use this model to predict proton emission half-lives of 13 nuclei in the same region, whose proton emission is energetically allowed or observed but not yet quantified in NUBASE2016.

A computational model for molecular interactions between curved slender fibers undergoing large 3D deformations with a focus on electrostatic, van der Waals, and repulsive steric forces

SummaryThis contribution proposes the first three‐dimensional (3D) beam‐beam interaction model for molecular interactions between curved slender fibers undergoing large deformations. While the general model is not restricted to a specific beam formulation, in the present work, it is combined with the geometrically exact beam theory and discretized via the finite element method. A direct evaluation of the total interaction potential for general 3D bodies requires the integration of contributions from molecule or charge distributions over the volumes of the interaction partners, leading to a six‐dimensional integral (two nested 3D integrals) that has to be solved numerically. Here, we propose a novel strategy to formulate reduced section‐section interaction laws for the resultant interaction potential between a pair of cross‐sections of two slender fibers such that only two one‐dimensional integrals along the fibers' length directions have to be solved numerically. This section‐section interaction potential (SSIP) approach yields a significant gain in efficiency, which is essential to enable the simulation of relevant time and length scales for many practical applications. In a first step, the generic structure of SSIP laws, which is suitable for the most general interaction scenario (eg, fibers with arbitrary cross‐section shape and inhomogeneous atomic/charge density within the cross‐section) is presented. Assuming circular, homogeneous cross‐sections, in a next step, specific analytical expressions for SSIP laws describing short‐range volume interactions (eg, van der Waals (vdW) or steric interactions) and long‐range surface interactions (eg, Coulomb interactions) are proposed. Besides ready‐to‐use expressions for the total interaction potential, also the resulting virtual work contributions, its finite element discretizations, as well as a suitable numerical regularization for the limit of zero separation are derived. The validity of the SSIP laws, as well as the accuracy and robustness of the general SSIP approach to beam‐beam interactions, is thoroughly verified by means of a set of numerical examples considering steric repulsion, electrostatic, or vdW adhesion.

Excitation-energy-dependent potential energy surfaces in the ternary breakup of Cf252

We study the excitation energy-dependent potential-energy surfaces (PESs) for both the spherical and deformed fragments from the ternary fragmentation (TF) of $^{252}\mathrm{Cf}$ at four different excitation energies of the fissioning parent nuclei. A two-dimensional minimization approach with respect to the charge numbers (${Z}_{1}, {Z}_{2}$, and ${Z}_{3}$) of the fragments has been used to minimize all possible ternary combinations, which are generated from the atomic-mass-evaluation (AME2016) data [Chin. Phys. C 41, 030003 (2017)]. To calculate the energy-dependent TF-PES, we used the temperature-dependent binding energies (TDBE), which are calculated as follows: the temperature-dependent ($T$-dependent) macroscopic liquid-drop model (LDM) energy proper due to Krappe's formula [Phys. Rev. C 59, 2640 (1999)] and the microscopic shell correction energies due to the analytical estimates of Myers and Swiatecki [Nucl. Phys. 81, 1 (1966)]. Furthermore, the shell correction energies and the nuclear deformations are also made $T$-dependent. In this study, the $T$-dependent total interaction potential between the ternary fragments is calculated for the fragments in a collinear geometry with the lightest fragment ${A}_{3}$ being in the middle of the two main fission fragments ${A}_{1}$ and ${A}_{2}$. From the TF-PES results with the use of spherical-shell corrections, a strong energy maximum in the PES is obtained around ${Z}_{3}=2$ with the ${Z}_{1}=50$ region due to the closed-shell effects of doubly magic nuclei. In addition to this, we also obtained some other significant energy maxima around the magic and/or semimagic numbers of nuclei. These energy maxima extend further with increasing excitation energy of the fissioning parent nuclei. We also found that the true-ternary-fragmentation (TTF) fragments are reasonably favored at high excitation energies. Furthermore, the effects of $T$-dependent deformations and the $T$-dependent deformed-shell corrections in the TF-PES of $^{252}\mathrm{Cf}$ are also studied. From the TF-PES results of deformed ternary fragments, we obtained the energy maximum around ${Z}_{3}=16$ region, which may be due to the larger ${\ensuremath{\beta}}_{2}$ deformation values. Furthermore, we also studied the ternary fragmentation yields and neutron emission from the excited fragments in the $^{10}\mathrm{Be}$-accompanied spontaneous ternary fission of $^{252}\mathrm{Cf}$ and compared our calculated results with the available experimental data.

A Diffusion Limit for the Parabolic Kuramoto--Sakaguchi Equation with Inertia

In this paper, we study a macroscopic description on the ensemble of Kuramoto oscillators with finite inertia in a random media characterized by a white noise. In a mesoscopic regime, it is well known that the dynamics of a large Kuramoto ensemble in a random media is governed by the Kuramoto--Sakaguchi--Fokker--Planck (in short, parabolic Kuramoto--Sakaguchi) equation for one-oscillator distribution function. For this parabolic Kuramoto--Sakaguchi equation, we present a global existence of weak solutions in any finite-time interval. Furthermore, we rescale the kinetic equation using the diffusion scaling, and formally derive a drift-diffusion equation by using Hilbert-like expansion in a small parameter $\varepsilon$. For the rigorous justification of this asymptotic limit, we introduce a new free energy functional ${\mathcal E}$ consisting of total mass, kinetic energy, entropy functional, and interaction potential and show the uniform boundedness of this free energy with respect to the small parameter $\varepsilon$. This uniform boundedness of ${\mathcal E}$ combined with $L^1$-compactness argument enables us to derive the drift-diffusion equation. We also classified all ${\mathcal C}^2$-stationary solutions to the drift-diffusion equation in terms of synchronization parameters $\kappa$ and $\sigma$.

Investigation of proton emission using deformed relativistic mean field densities

The proton emission in neutron deficient nuclei with [Formula: see text] has been investigated within the framework of axially deformed relativistic mean field (RMF) theory using NL3 and density-dependent DD-ME1 and DD-ME2 parameters. The quasi-bound states from which the proton emission is probable are determined. The RMF densities are folded with the M3Y effective nucleon–nucleon interaction to obtain the nuclear potential. The total interaction potential consisting of nuclear, Coulomb and centrifugal potentials is used to calculate the proton decay half-lives using the Wentzel–Kramers–Brillouin (WKB) approximation. For this, we have used the [Formula: see text], [Formula: see text] being the single-particle energy of the decaying proton near the Fermi surface. The calculated proton decay half-lives for different nuclei are in consonance with experimental data.

A New Approach for Calculating Cohesive Energy of Solid Neon Based on the First Principles

Based on the first principles and quantum mechanics, a new approach is put forward to calculate the cohesive energy of face-centered cubic solid neon, in which both the two-body and the total many-body interaction potentials are reasonably emphasized by a new combination formula. It shows that the new scheme is a simple and accurate tool to understand the high-pressure behaviors of solid neon, and it will be applied to calculate the compression curves of dense Helium, Argon, Krypton and Xenon at very high pressures. It is expected that this method can be applicable to all rare gas, including the gas, solid, and liquid phase regions, even of molecular systems, ionic systems.

Systematic study of proton radioactivity of spherical proton emitters within various versions of proximity potential formalisms

In this work we present a systematic study of the proton radioactivity half-lives of spherical proton emitters within the Coulomb and proximity potential model. We investigate 28 different versions of the proximity potential formalisms developed for the description of proton radioactivity, $\mathcal{\alpha}$ decay and heavy particle radioactivity. It is found that 21 of them are not suitable to deal with the proton radioactivity, because the classical turning points $r_{\text{in}}$ cannot be obtained due to the fact that the depth of the total interaction potential between the emitted proton and the daughter nucleus is above the proton radioactivity energy. Among the other 7 versions of the proximity potential formalisms, it is Guo2013 which gives the lowest rms deviation in the description of the experimental half-lives of the known spherical proton emitters. We use this proximity potential formalism to predict the proton radioactivity half-lives of 13 spherical proton emitters, whose proton radioactivity is energetically allowed or observed but not yet quantified, within a factor of 3.71.

All-atom computations with irreversible Markov chains.

We apply the irreversible event-chain Monte Carlo (ECMC) algorithm to the simulation of dense all-atom systems with long-range Coulomb interactions. ECMC is event-driven and exactly samples the Boltzmann distribution. It neither uses time-step approximations nor spatial cutoffs on the range of the interaction potentials. Most importantly, it need not evaluate the total Coulomb potential and thus circumvents the major computational bottleneck of traditional approaches. It only requires the derivatives of the two-particle Coulomb potential, for which we discuss mutually consistent choices. ECMC breaks up the total interaction potential into factors. For particle systems made up of neutral dipolar molecules, we demonstrate the superior performance of dipole-dipole factors that do not decompose the Coulomb potential beyond the two-molecule level. We demonstrate that these long-range factors can nevertheless lead to local lifting schemes, where subsequently moved particles are mostly close to each other. For the simple point-charge water model with flexible molecules (SPC/Fw), which combines the long-ranged intermolecular Coulomb potential with hydrogen-oxygen bond-length vibrations, a flexible hydrogen-oxygen-hydrogen bond angle, and Lennard-Jones oxygen-oxygen potentials, we break up the potential into factors containing between two and six particles. For this all-atom liquid-water model, we demonstrate that the computational complexity of ECMC scales very well with the system size. This is achieved in a pure particle-particle framework, without the interpolating mesh required for the efficient implementation of other modern Coulomb algorithms. Finally, we discuss prospects and challenges for ECMC and outline several future applications.