$K_{l_4}$ DECAY ANALYSIS IN A PARAMETER-FREE RELATIVISTIC MODEL

1992 ◽  
Vol 07 (24) ◽  
pp. 2223-2227
Author(s):  
R. RAMANATHAN
Keyword(s):  
Form Factors ◽  
Relativistic Model ◽  
Large N ◽  
Hadron Mass ◽  
Free Model ◽  
Free Parameters ◽  
Experimental Values ◽  
Almost All ◽  
Best Fit ◽  
Good Agreement

The dimensionless form factors fs(0), g(0), h(0) and λ which account for almost all the microscopic details of the [Formula: see text] decay are computed in an integrated QCD oriented Bethe-Salpeter framework, where all the free parameters involved in the formalism are fixed by the best fit with the Hadron mass spectroscopy, so that for the present evaluation we have a parameter-free model. The values of the form factors so obtained are in good agreement with the experimental values and the agreement is comparable with the recent similar calculations using large-Nc limits in chiral QCD theory.

DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

2019 ◽  
Author(s):  
Danilo Carmona ◽  
Pablo Jaque ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Reference Value ◽  
Basis Set ◽  
Basis Sets ◽  
Mean Deviation ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
The Mean ◽  
Experimental Values ◽  
High Level ◽  
Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

Systematic calculations of energy levels and transitions rates in Mo XXVIII

2020 ◽  
Vol 75 (8) ◽  
pp. 739-747
Author(s):  
Feng Hu ◽  
Yan Sun ◽  
Maofei Mei
Keyword(s):  
Energy Levels ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Data Sets ◽  
Electron Systems ◽  
Excitation Energies ◽  
Experimental Values ◽  
Qed Effects ◽  
Hyperfine Structures ◽  
Good Agreement

AbstractComplete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Landé gJ-factors and E1, E2, M1, and M2 line strengths, oscillator strengths, transitions rates are reported for the low-lying 41 levels of Mo XXVIII, belonging to the n = 3 states (1s22s22p6)3s23p3, 3s3p4, and 3s23p23d. High-accuracy calculations have been performed as benchmarks in the request for accurate treatments of relativity, electron correlation, and quantum electrodynamic (QED) effects in multi-valence-electron systems. Comparisons are made between the present two data sets, as well as with the experimental results and the experimentally compiled energy values of the National Institute for Standards and Technology wherever available. The calculated values including core-valence correction are found to be in a good agreement with other theoretical and experimental values. The present results are accurate enough for identification and deblending of emission lines involving the n = 3 levels, and are also useful for modeling and diagnosing plasmas.

scholarly journals DFT calculation and assignment of vibrational spectra of aryl and alkyl chlorophosphates

2014 ◽  
Vol 12 (2) ◽  
pp. 153-163
Author(s):  
Viktor Anishchenko ◽  
Vladimir Rybachenko ◽  
Konstantin Chotiy ◽  
Andrey Redko
Keyword(s):  
Vibrational Spectra ◽  
Basis Sets ◽  
Heavy Atoms ◽  
Wide Range ◽  
Complete Assignment ◽  
Key Factor ◽  
Polarization Functions ◽  
Experimental Values ◽  
Semi Empirical ◽  
Good Agreement

AbstractDFT calculations of vibrational spectra of chlorophosphates using wide range of basis sets and hybrid functionals were performed. Good agreement between calculated and experimental vibrational spectra was reached by the combination of non-empirical functional PBE0 with both middle and large basis sets. The frequencies of the stretching vibrations of the phosphate group calculated using semi-empirical functional B3LYP for all basis sets deviate significantly from the experimental values. The number of polarization functions on heavy atoms was shown to be a key factor for the calculation of vibrational frequencies of organophosphates. The importance of consideration of all the stable rotamers for a complete assignment of fundamental modes was shown.

scholarly journals Structural elastic and thermal properties of SrxCd1−x O mixed compounds — a theoretical approach

2014 ◽  
Vol 32 (3) ◽  
pp. 350-357
Author(s):  
Purvee Bhardwaj
Keyword(s):  
Phase Transition ◽  
Vibrational Energy ◽  
Zero Point ◽  
Study Phase ◽  
Energy Effect ◽  
Phase Transition Pressure ◽  
Vegard’S Law ◽  
Extended Interaction ◽  
Experimental Values ◽  
Good Agreement

AbstractIn the present paper, the structural and mechanical properties of alkaline earth oxides mixed compound SrxCd1−x O (0 ≤ x ≤ 1) under high pressure have been reported. An extended interaction potential (EIP) model, including the zero point vibrational energy effect, has been developed for this study. Phase transition pressures are associated with a sudden collapse in volume. Phase transition pressure and associated volume collapses [ΔV (Pt)/V(0)] calculated from this approach are in good agreement with the experimental values for the parent compounds (x = 0 and x = 1). The results for the mixed crystal counterparts are also in fair agreement with experimental data generated from the application of Vegard’s law to the data for the parent compounds.

The Thermodynamics Calculation of Mg-Zn Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 447-450
Author(s):  
Tian Mo Liu ◽  
Hong Yi Zhou ◽  
Fu Sheng Pan
Keyword(s):  
Excess Entropy ◽  
Formation Enthalpy ◽  
Miedema Model ◽  
Activity Curve ◽  
Calculation Results ◽  
Experimental Values ◽  
Zn Alloy ◽  
Zn Alloys ◽  
Good Agreement

In the present work Miedema model has been developed, and the formation enthalpy of Mg-Zn alloys and the activity curve of Zn in Mg-Zn alloy at 1000K have been calculated according to the Miedema model. The calculation results showed that the formation enthalpy of Mg-Zn was small, and the excess entropy attributes a lot to the result. When excess enthopy was considered, the calculation results were found to be in good agreement with the experimental values.

scholarly journals STATISTICAL STUDIES ON PROTEIN POLYMORPHISM IN NATURAL POPULATIONS II. GENE DIFFERENTIATION BETWEEN POPULATIONS

Genetics ◽  
1978 ◽  
Vol 88 (2) ◽  
pp. 367-390
Author(s):  
Ranajit Chakraborty ◽  
Paul A Fuerst ◽  
Masatoshi Nei
Keyword(s):  
Genetic Differentiation ◽  
Natural Populations ◽  
Drift Theory ◽  
Alternative Hypotheses ◽  
Mean And Variance ◽  
Statistical Studies ◽  
Different Populations ◽  
Using Data ◽  
Almost All ◽  
Good Agreement

ABSTRACT With the aim of testing the validity of the mutation-drift hypothesis, we examined the pattern of genetic differentiation between populations by using data from Drosophila, fishes, reptiles, and mammals. The observed relationship between genetic identity and correlation of heterozygosities of different populations or species was generally in good agreement with the theoretical expectations from the mutation-drift theory, when the variation in mutation rate among loci was taken into account. In some species of Drosophila, however, the correlation was unduly high. The relationship between the mean and variance of genetic distance was also in good agreement with the theoretical prediction in almost all organisms. We noted that both the distribution of heterozygosity within species and the pattern of genetic differentiation between species can be explained by the same set of genetic parameters in each group of organisms. Alternative hypotheses for explaining these observations are discussed.

scholarly journals Variation in rms charge radii of deuteron and helium nuclei with s\sqrt s

Nukleonika ◽  
2020 ◽  
Vol 65 (4) ◽  
pp. 211-215
Author(s):  
Sarwat Zahra ◽  
Bushra Shafaq ◽  
Bushra Kanwal ◽  
Nosheen Akbar
Keyword(s):  
Center Of Mass ◽  
Form Factors ◽  
Mass Energy ◽  
Charge Radii ◽  
Center Of Mass Energy ◽  
Theoretical Predictions ◽  
Dependent Form ◽  
Energy Dependent ◽  
The Relationship ◽  
Good Agreement

AbstractBy considering energy-dependent form factors extracted from generalized Chou–Yang model, root mean square (rms) charge radii of deuteron and helium nuclei (alpha) are predicted at different values of center of mass energy which are in good agreement with theoretical predictions and experimental results. The rms radius is inversely proportional to mass of nuclei. Besides, the relationship between radii and energy are also derived.

scholarly journals The Nuclear Structure for Exotic Neutron-Rich of 42, 43, 45,47K Nuclei

2016 ◽  
Vol 13 (1) ◽  
pp. 146-154
Author(s):  
Baghdad Science Journal
Keyword(s):  
Magnetic Dipole ◽  
Electron Scattering ◽  
Dipole Moments ◽  
Exotic Nucleus ◽  
Form Factors ◽  
Model Space ◽  
Density Distributions ◽  
Plane Wave Born Approximation ◽  
Magnetic Electron ◽  
Good Agreement

In this paper the proton, neutron and matter density distributions and the corresponding root mean square (rms) radii of the ground states and the elastic magnetic electron scattering form factors and the magnetic dipole moments have been calculated for exotic nucleus of potassium isotopes K (A= 42, 43, 45, 47) based on the shell model using effective W0 interaction. The single-particle wave functions of harmonic-oscillator (HO) potential are used with the oscillator parameters b. According to this interaction, the valence nucleons are asummed to move in the d3f7 model space. The elastic magnetic electron scattering of the exotic nuclei 42K (J?T= 2- 2), 43K(J?T=3/2+ 5/2), 45K (J?T= 3/2+ 7/2) and 47K (J?T= 1/2+ 9/2) investigated through Plane Wave Born Approximation (PWBA). The inclusion of core polarization effect through the effective g-factors is adequate to obtain a good agreement between the predicted and the measured magnetic dipole moments.

scholarly journals The effect of short range correlation on the inelastic C4 form factors of 18O nucleus

2019 ◽  
Vol 13 (28) ◽  
pp. 130-141
Author(s):  
Abdullah S. Mdekil
Keyword(s):  
Charge Density ◽  
Short Range ◽  
Form Factors ◽  
Model Space ◽  
Charge Density Distribution ◽  
Short Range Correlation ◽  
Range Correlation ◽  
Free Parameters ◽  
State Charge ◽  
Short Range Correlations

The effect of short range correlations on the inelastic longitudinalCoulomb form factors for different states of J   4 , T  1withexcitation energies 3.553,7.114, 8.960 and 10.310 MeV in 18O isanalyzed. This effect (which depends on the correlation parameter )is inserted into the ground state charge density distribution throughthe Jastrow type correlation function. The single particle harmonicoscillator wave function is used with an oscillator size parameter b.The parameters  and b are considered as free parameters, adjustedfor each excited state separately so as to reproduce the experimentalroot mean square charge radius of 18O. The model space of 18O doesnot contribute to the transition charge density. As a result, theinelastic Coulomb form factors of 18O comes absolutely from thecore polarization transition charge density. According to thecollective modes of nuclei, the core polarization transition chargedensity is assumed to have the form of Tassie shape. It is found thatthe introduction of the effect of short range correlations is necessaryfor obtaining a remarkable modification in the calculated inelasticlongitudinal Coulomb form factors and considered as an essential forexplanation the data amazingly throughout the whole range ofconsidered momentum transfer.

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