Parity-mixing above 30 MeV excitation energy in the 4He system

1981 ◽  
Vol 59 (6) ◽  
pp. 765-768
Author(s):  
J. J. Bevelacqua
Keyword(s):  
Excitation Energy ◽  
Effective Potential ◽  
Energy Levels ◽  
Model Space ◽  
Wave Functions ◽  
Order Of Magnitude ◽  
Text Model ◽  
Body Potential

Parity-induced circular polarizations have been calculated for energy levels between 30 and 90 MeV excitation energy in the 4He system. The effective potential of Box, McKellar, Pick, and Lassey (BMPL) is utilized in the calculations. The results are based on detailed 4He wave functions which are calculated in a [Formula: see text] model space. The calculated circular polarizations (Pγ) are largest for Jπ = 1+ states at about 75 MeV excitation. These Pγ values are between 10−5 and 10−6 and are of the same order of magnitude as transitions measured in the 2H, 181Ta, and 203Tl systems. Circular polarizations based on the BMPL potential are within 15% of the Pγ values derived from the weak two-body potential of Desplanques and Missimer for the largest transitions considered in this study.

Parity-mixing below 30 MeV excitation energy in the 4He system

1980 ◽  
Vol 58 (2) ◽  
pp. 249-254
Author(s):  
J. J. Bevelacqua
Keyword(s):  
Matrix Element ◽  
Excitation Energy ◽  
Enhancement Factor ◽  
Neutral Current ◽  
Model Space ◽  
Wave Functions ◽  
Matrix Elements ◽  
Least Squares Fit ◽  
Mixing Matrix ◽  
Text Model

Parity-mixing matrix elements for ΔT = 0 and ΔT = 1 transitions are calculated for selected transitions below 30 MeV excitation energy in the 4He system. The effective potential of Box, McKellar, Pick, and Lassey is utilized in the calculations. The results are based on detailed 4He wave functions which are calculated in a [Formula: see text] model space. The calculated parity-mixing matrix elements are in qualitative agreement with those predicted on the basis of a least-squares fit to 2 ≤ A ≤ 181 data by Desplanques and Missimer. The ΔT = 0 matrix element is calculated between the (0+,0)20.1 MeV level and the (0−,0)21.1 MeV level, while the ΔT = 1 matrix element is evaluated between the (1+,0) 25.5 MeV level and the (1−,1) 27.4 MeV state. The ΔT = 0 and ΔT = 1 calculations lead to parity-mixing matrix elements of −0.014 and +0.049 eV, respectively. These matrix elements correspond to parity-mixed components which are 10−8 smaller than the dominant parity component of an energy level. The parity-non-conserving (PNC) transitions lead to circular polarizations of 1.2 × 10−7 for the (1+,0) 25.5 MeV level and −2.2 × 10−8 for the (1−,1) 27.4 MeV level. The inclusion of a neutral current enhancement factor of about 10 increases the ΔT = 1 parity-mixing matrix element by about a factor of two.

Shell evolution for neutron-rich 46–54Ar isotopes in the full and truncated fp neutron model spaces

2021 ◽  
Author(s):  
Hussam A. Bahr ◽  
Ali A. Alzubadi
Keyword(s):  
Excitation Energy ◽  
Shell Model ◽  
Transition Probability ◽  
Energy Levels ◽  
Drip Line ◽  
Model Calculations ◽  
Effective Interactions ◽  
Argon Isotopes ◽  
Model Spaces ◽  
Text Model

The shell evolution of even–even drip line argon isotopes [Formula: see text] has been investigated via the shell model calculations using SDPF-U and SDPF-NR two-body effective interactions in two different shell model spaces [Formula: see text] and [Formula: see text]. In this work, the energy of first [Formula: see text], reduced transition probability [Formula: see text], excitation energy levels as well as how the proton shells evolve with [Formula: see text] have been studied. Excellent agreements were obtained for the first [Formula: see text] level along the investigated isotopes within [Formula: see text] and [Formula: see text] model spaces.

The sensitization of laser-induced heat of Er3+ doped Y2O3 nanocrystals by codoped with Mn2+

2015 ◽  
Vol 29 (22) ◽  
pp. 1550158
Author(s):  
Yunfeng Bai ◽  
Minjie Luan ◽  
Linjun Li ◽  
Zhelong He ◽  
Dongyu Li
Keyword(s):  
Power Density ◽  
Thermal Emission ◽  
Energy Levels ◽  
Excitation Power ◽  
Threshold Power ◽  
Excitation Power Density ◽  
Ir Laser ◽  
Order Of Magnitude ◽  
Low Threshold ◽  
Density Threshold

Low threshold power density cw laser-induced heat has been observed in [Formula: see text] and [Formula: see text] codoped [Formula: see text] nanocrystals under excitation by a 980 nm IR laser. Codoped [Formula: see text] remarkably reduces the power density threshold of laser-induced heat compared with [Formula: see text] doped [Formula: see text] nanocrystals. When the excitation power density exceed [Formula: see text], [Formula: see text] codoped [Formula: see text] nanocrystals emit strong blackbody radiation. The thermal emission of [Formula: see text] should originate from the multiphonon relaxation between neighboring energy levels. One additional UC-PL enhancement is observed. The UC-PL intensity can be enhanced by an order of magnitude through high temperature calcination caused by light into heat.

scholarly journals An Effective Potential for Frenkel Excitons

2020 ◽  
Author(s):  
Bartosz Błasiak ◽  
Wojciech Bartkowiak ◽  
Robert Władysław Góra
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Efficient Method ◽  
Effective Potential ◽  
Excitation Energy Transfer ◽  
Computationally Efficient ◽  
Frenkel Excitons

Excitation energy transfer (EET) is a ubiquitous process in life and materials sciences. Here, a new and computationally efficient method of evaluating the electronic EET couplings between interacting chromophores is...

No-scale supergravity inflation: A bridge between string theory and particle physics?

2016 ◽  
Vol 25 (14) ◽  
pp. 1630027 ◽  
Author(s):  
John Ellis
Keyword(s):  
Supergravity Models ◽  
String Theory ◽  
Effective Potential ◽  
Particle Physics ◽  
Model Building ◽  
Inflationary Model ◽  
New Wave ◽  
Microwave Background ◽  
Supergravity Theory ◽  
Text Model

The plethora of recent and forthcoming data on the cosmic microwave background (CMB) data are stimulating a new wave of inflationary model-building. Naturalness suggests that the appropriate framework for models of inflation is supersymmetry. This should be combined with gravity in a supergravity theory, whose specific no-scale version has much to commend it, e.g. its derivation from string theory and the flat directions in its effective potential. Simple no-scale supergravity models yield predictions similar to those of the Starobinsky [Formula: see text] model, though some string-motivated versions make alternative predictions. Data are beginning to provide interesting constraints on the rate of inflaton decay into Standard Model particles. In parallel, LHC and other data provide significant constraints on no-scale supergravity models, which suggest that some sparticles might have masses close to present experimental limits.

scholarly journals Intercombination Transitions between Levels X1Σg+ and A 3Πu in C2

1987 ◽  
Vol 120 ◽  
pp. 103-105
Author(s):  
J. Le Bourlot ◽  
E. Roueff
Keyword(s):  
Transition Probabilities ◽  
Energy Levels ◽  
Wave Functions ◽  
Spin Orbit Coupling ◽  
Energy Matrix ◽  
First Order ◽  
Emission Transition ◽  
Intercombination Transition ◽  
The One ◽  
Potential Curves

We present a new calculation of intercombination transition probabilities between levels X1Σg+ and a 3Πu of the C2 molecule. Starting from experimental energy levels, we calculate RKR potential curves using Leroy's Near Dissociation Expansion (NDE) method; these curves give us wave functions for all levels of interest. We then compute the energy matrix for the four lowest states of C2, taking into account Spin-Orbit coupling between a 3Πu and A 1Πu on the one hand and X 1Σ+g and b 3Σg− on the other. First order wave functions are then derived by diagonalization. Einstein emission transition probabilities of the Intercombination lines are finally obtained.

scholarly journals Large Scale Shell Model Calculations of the Negative-Parity States Structure in 24Mg Nucleus

2021 ◽  
Vol 66 (4) ◽  
pp. 293
Author(s):  
A.A. Al-Sammarraie ◽  
F.A. Ahmed ◽  
A.A. Okhunov
Keyword(s):  
Shell Model ◽  
Large Scale ◽  
Transition Probabilities ◽  
Transition Probability ◽  
Energy Levels ◽  
Form Factors ◽  
Model Space ◽  
Negative Parity ◽  
Matrix Elements ◽  
Model Calculations

The negative-parity states of 24Mg nucleus are investigated within the shell model. We are based on the calculations of energy levels, total squared form factors, and transition probability using the p-sd-pf (PSDPF) Hamiltonian in a large model space (0 + 1) hW. The comparison between the experimental and theoretical states showed a good agreement within a truncated model space. The PSDPF-based calculations successfully reproduced the data on the total squared form factors and transition probabilities of the negative-parity states in 24Mg nucleus. These quantities depend on the one-body density matrix elements that are obtained from the PSDPF Hamiltonian. The wave functions of radial one-particle matrix elements calculated with the harmonic-oscillator potential are suitable to predict experimental data by changing the center-of-mass corrections.

Influence of Hot Electron Scattering and Electron–Phonon Interactions on Thermal Boundary Conductance at Metal/Nonmetal Interfaces

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Ashutosh Giri ◽  
Brian M. Foley ◽  
Patrick E. Hopkins
Keyword(s):  
Phonon Scattering ◽  
Energy Levels ◽  
Golden Rule ◽  
Energy Coupling ◽  
Hot Electron ◽  
Nonequilibrium Electron ◽  
Simplified Approach ◽  
Thermal Boundary Conductance ◽  
Order Of Magnitude ◽  
Unique Mechanism

It has recently been demonstrated that under certain conditions of electron nonequilibrium, electron to substrate energy coupling could represent a unique mechanism to enhance heat flow across interfaces. In this work, we present a coupled thermodynamic and quantum mechanical derivation of electron–phonon scattering at free electron metal/nonmetal substrate interfaces. A simplified approach to the Fermi's Golden Rule with electron energy transitions between only three energy levels is adopted to derive an electron–phonon diffuse mismatch model, that account for the electron–phonon thermal boundary conductance at metal/insulator interfaces increases with electron temperature. Our approach demonstrates that the metal-electron/nonmetal phonon conductance at interfaces can be an order of magnitude larger than purely phonon driven processes when the electrons are driven out of equilibrium with the phonons, consistent with recent experimental observations.

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