Systematic of alpha decay half-lives: role of quantization condition

2021 ◽  
pp. 1-9
Author(s):  
M. Hosseini-Tabatabaei ◽  
S.A. Alavi ◽  
V. Dehghani
Keyword(s):  
Alpha Decay ◽  
Tunneling Probability ◽  
Quantization Condition ◽  
Nuclear Potential ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Wkb Method ◽  
Saxon Potential ◽  
Alpha Emitters

Using the semiclassical WKB method and considering the WKB quantization condition, the alpha decay half-lives of 420 alpha emitters were calculated with eight forms of the proximity and Woods–Saxon type potentials. The effect of quantization condition on the nuclear potential, effective potential, assault frequency, tunneling probability, alpha decay half-life, and root mean square deviation between theory and the experiment were investigated. Significant differences between calculated half-lives with and without inclusion of the quantization condition were observed specially for proximity potentials. By including the quantization, the Woods–Saxon potential was found as the best potential for even–even, even–odd, odd–even, odd–odd, and all alpha emitters. The quantization condition normalized the nuclear potentials. Therefore, by considering this condition, the thirteen forms of the prox77 potential with different sets of the surface energy and surface asymmetry constants gave the same results. This result was justified with two sets of parameters.

Role of constant value of surface diffuseness in alpha decay half-lives of superheavy nuclei

2018 ◽  
Vol 33 (14) ◽  
pp. 1850080 ◽  
Author(s):  
V. Dehghani ◽  
S. A. Alavi ◽  
Kh. Benam
Keyword(s):  
Alpha Decay ◽  
Tunneling Probability ◽  
Nuclear Potential ◽  
Superheavy Nuclei ◽  
Wkb Method ◽  
Alpha Emitters ◽  
Surface Diffuseness ◽  
Diffuseness Parameter ◽  
Good Agreement

By using WKB method and considering deformed Woods–Saxon nuclear potential, deformed Coulomb potential, and centrifugal potential, the alpha decay half-lives of 68 superheavy alpha emitters have been calculated. The effect of the constant value of surface diffuseness parameter in the range of 0.1 [Formula: see text]a [Formula: see text] 0.9 (fm) on the potential barrier, tunneling probability, assault frequency, and alpha decay half-lives has been investigated. Significant differences were observed for alpha decay half-lives and decay quantities in this range of surface diffuseness. Good agreement between calculated half-lives with fitted surface diffuseness parameter a = 0.54 (fm) and experiment was observed.

Calculation of Q-value and half-life of alpha-decay chains of superheavy elements using double folding method

2019 ◽  
Vol 28 (06) ◽  
pp. 1950045 ◽  
Author(s):  
B. Nandana ◽  
R. Rahul ◽  
S. Mahadevan
Keyword(s):  
Half Life ◽  
Decay Chain ◽  
Alpha Decay ◽  
Superheavy Elements ◽  
Nuclear Potential ◽  
Wkb Method ◽  
Saxon Potential ◽  
Q Value ◽  
Double Folding

[Formula: see text]-value and half-life of elements in alpha decay chain of [Formula: see text]117, [Formula: see text]117, [Formula: see text]116 and [Formula: see text]116 were calculated using the Nuclear potential generated by double folding procedure and using the WKB method treating the alpha decay as a tunneling problem. The nuclear potential was parameterized using Woods–Saxon potential. Using this approach, the [Formula: see text]-value and half-life of next heaviest element in the alpha decay chain of element [Formula: see text]116 is predicted. It is proposed to use this to predict the [Formula: see text]-value and half-life of other higher elements in different alpha decay chains.

The alpha-decay chains and decay mode predictions of the nuclei Z = 118, 119 and 120

2020 ◽  
Vol 29 (07) ◽  
pp. 2050053
Author(s):  
F. Koyuncu ◽  
A. Soylu
Keyword(s):  
Decay Mode ◽  
Half Life ◽  
Spontaneous Fission ◽  
Theoretical Models ◽  
Alpha Decay ◽  
Quantization Condition ◽  
Experimental Investigations ◽  
Universal Curve ◽  
Wkb Method ◽  
Decay Modes

The alpha decay (AD) chains of the nuclei having [Formula: see text], 119 and 120 have been investigated in terms of different theoretical models. Decay mode results that are presented in this study have been probed over the possible isotopes of the aforementioned nuclei. In the decay mode predictions, the formula of Bao et al. and the formula proposed by Soylu have been used to calculate the spontaneous fission (SF) half-lives. The AD half-lives have been computed by using the Denisov and Khuedenko, Royer, Horoi, the universal decay law (UDL), the Viola–Seaborg–Sobiczewski (VSS), the universal curve (UNIV) formulas and Wentzel–Kramers–Brillouin (WKB) approximation with Bohr–Sommerfeld quantization condition for the nuclei that have the measured experimental half-lives. Therefore, the rms values of the results of the related expressions and WKB method have been determined, in this way, AD half-life calculations of the [Formula: see text], 119 and 120 nuclei have been performed. According to the obtained results, SF half-life values for Bao et al. and Soylu are quite different from one approach to another, the predictions on decay modes of the [Formula: see text], 119 and 120 nuclei show differences. The decay modes produced by using different models used in this study would be important for the predictions of the future experimental investigations.

STOCHASTIC SPIKING COHERENCE IN COUPLED SUBTHRESHOLD MORRIS-LECAR NEURONS

2009 ◽  
Vol 23 (05) ◽  
pp. 703-710 ◽  
Author(s):  
WOOCHANG LIM ◽  
SANG-YOON KIM
Keyword(s):  
Coherent State ◽  
Order Parameter ◽  
Noise Intensity ◽  
Large Range ◽  
Large Population ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Coherence Measure ◽  
The Mean

We consider a large population of globally coupled subthreshold Morris-Lecar neurons. By varying the noise intensity D, we numerically investigate stochastic spiking coherence (i.e., collective coherence between noise-induced neural spikings). As D passes a lower threshold, a transition from an incoherent to a coherent state occurs because of a constructive role of noise to stimulate coherence between noise-induced spikings. However, when passing a higher threshold of D, another transition from a coherent to an incoherent state takes place due to a destructive role of noise to spoil the spiking coherence. Such an incoherence-coherence-incoherence transition is well-described in terms of the order parameter which is just the mean square deviation of the global potential. In the coherent regime, we also characterize the degree of stochastic spiking coherence by using a coherence measure which reflects the degree of "resemblance" of the global potential to the local potential. Thus, stochastic spiking coherence with large coherence measure is found to occur over a large range of intermediate noise intensity.

EFFECT OF NUCLEAR DEFORMATION ON THE POTENTIAL BARRIER AND ALPHA-DECAY HALF-LIVES OF SUPERHEAVY NUCLEI

2013 ◽  
Vol 28 (16) ◽  
pp. 1350065 ◽  
Author(s):  
M. R. PAHLAVANI ◽  
S. A. ALAVI ◽  
N. TAHANIPOUR
Keyword(s):  
Potential Barrier ◽  
Alpha Decay ◽  
Superheavy Elements ◽  
Nuclear Potential ◽  
Superheavy Nuclei ◽  
Nuclear Deformation ◽  
Centrifugal Term ◽  
Wkb Method ◽  
Theory And Experiment ◽  
Good Agreement

The alpha-decay half lives of superheavy elements have been calculated in the framework of WKB method. The effective potential has been considered as summation of the deformed Woods–Saxon nuclear potential, deformed Coulomb potential and centrifugal term. The quadrupole, hexadecapole and hexacontatetrapole deformations have been included in the calculation. The effect of hexacontatetrapole deformation on the potential barrier has been presented, separately. The good agreement between theory and experiment has been observed for alpha-decay half-lives of heavy and superheavy elements.

scholarly journals Decaimento Alpha: Uma Abordagem Por Tunelamento Quântico

2019 ◽  
Vol 1 (46) ◽  
pp. 99
Author(s):  
Daniel Borges Silva ◽  
Francisco Florêncio Batista Júnior
Keyword(s):  
Decay Rate ◽  
Atomic Number ◽  
Coulomb Potential ◽  
Quantum Tunneling ◽  
Decay Constant ◽  
Alpha Decay ◽  
Particle Energy ◽  
Tunneling Probability ◽  
Wkb Method ◽  
Alpha Radiation

The present work sought to deduce the alpha decay theory based on quantum tunneling and using approximations in the resolution of the Schrödinger equation for Coulomb potential. It was possible to find the alpha decay constant analytically. One of the approaches used was the WKB method for solving differential equations, by which the Gamow factor was reached. From this point on, it was possible to identify the dependence of the decay rate with the energy of the radiation, as well as the atomic number. Besides that, we could understand the behavior of the tunneling probability with respect to some variables such as emitted particle energy and atomic number of the nucleus that decays. With this research we can help researchers in general in the study of alpha radiation.

scholarly journals A C++ library for protein sub-structure search

2020 ◽  
Author(s):  
Jianfu Zhou ◽  
Gevorg Grigoryan
Keyword(s):  
Data Mining ◽  
Structural Biology ◽  
Protein Structures ◽  
Structural Motif ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Structure Search ◽  
Program Interface ◽  
Programmatic Access

AbstractSummaryMASTER is a previously published algorithm for protein sub-structure search. Given a database of protein structures and a query structural motif, composed of multiple disjoint segments, it finds all sub-structures from the database that align onto the query to within a pre-specified backbone root-mean-square deviation. Here, we present an improved version of the algorithm, MASTER v.2, in the form of an open-source C++ Application Program Interface library, thereby providing programmatic access to structure search functionality. An entirely reorganized approach to database representation now enables large structural databases to be stored in memory, further simplifying development of automated search-based methods. Given the increasingly important role of structure-based data mining, our improved implementation should find ample uses in structural biology applications.AvailabilityMASTER is available at https://grigoryanlab.org/master/[email protected]

Alpha decay half-lives of superheavy nuclei 104 ≤ Z ≤ 125

2021 ◽  
pp. 2150071
Author(s):  
L. Vasanthi ◽  
N. S. Rajeswari
Keyword(s):  
Liquid Drop ◽  
Alpha Decay ◽  
Nuclear Potential ◽  
Superheavy Nuclei ◽  
Heavy Nuclei ◽  
Exponential Potential ◽  
Heavy And Superheavy Nuclei ◽  
Surface Diffuseness ◽  
Structure Formula

In order to describe scattering, fusion, fission and ground state masses, Krappe and collaborators developed unified nuclear potential, by generalizing liquid drop model. They have incorporated phenomenological parameters accounting for the attractive force between two separated fragments. One of the phenomenological parameters involved in this model is the range of folded Yukawa function, which accounts for surface diffuseness of the potential and short range attractive interaction. The role of range of folding function of Yukawa-plus-exponential potential is analyzed for alpha decay of heavy and superheavy nuclei. Significant effect of this function is noted in preformation probability which improves the accuracy of half-lives of alpha decay. Half-lives for alpha decay are better obtained for two values of the range of folding function 0.54 and 0.8[Formula: see text]fm for heavy and superheavy mass regions, respectively. The study confirms the associated shell structure [Formula: see text] in heavy nuclei and [Formula: see text] and [Formula: see text] in superheavy nuclei. The calculations are extended to predict the half-lives of superheavy nuclei with [Formula: see text] and [Formula: see text] which are not yet synthesized experimentally.

scholarly journals GNINA 1.0: molecular docking with deep learning

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Andrew T. McNutt ◽  
Paul Francoeur ◽  
Rishal Aggarwal ◽  
Tomohide Masuda ◽  
Rocco Meli ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Root Mean Square ◽  
Root Mean Square Deviation ◽  
Computational Cost ◽  
Scoring Function ◽  
Binding Pocket ◽  
Protein Docking ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Autodock Vina

AbstractMolecular docking computationally predicts the conformation of a small molecule when binding to a receptor. Scoring functions are a vital piece of any molecular docking pipeline as they determine the fitness of sampled poses. Here we describe and evaluate the 1.0 release of the Gnina docking software, which utilizes an ensemble of convolutional neural networks (CNNs) as a scoring function. We also explore an array of parameter values for Gnina 1.0 to optimize docking performance and computational cost. Docking performance, as evaluated by the percentage of targets where the top pose is better than 2Å root mean square deviation (Top1), is compared to AutoDock Vina scoring when utilizing explicitly defined binding pockets or whole protein docking. Gnina, utilizing a CNN scoring function to rescore the output poses, outperforms AutoDock Vina scoring on redocking and cross-docking tasks when the binding pocket is defined (Top1 increases from 58% to 73% and from 27% to 37%, respectively) and when the whole protein defines the binding pocket (Top1 increases from 31% to 38% and from 12% to 16%, respectively). The derived ensemble of CNNs generalizes to unseen proteins and ligands and produces scores that correlate well with the root mean square deviation to the known binding pose. We provide the 1.0 version of Gnina under an open source license for use as a molecular docking tool at https://github.com/gnina/gnina.

Sign in / Sign up

Export Citation Format

Share Document