THE INTERNAL EXCITATION OF THE GAS OF INDEPENDENT PARTICLES IN A TIME DEPENDENT POTENTIAL

2011 ◽  
Vol 20 (02) ◽  
pp. 292-298 ◽  
Author(s):  
J. P. BLOCKI ◽  
A. G. MAGNER ◽  
I. S. YATSYSHYN
Keyword(s):  
Small Amplitude ◽  
Equilibrium Shape ◽  
Mean Field ◽  
Time Dependent ◽  
Nuclear Model ◽  
Quantum Gas ◽  
Excitation Energies ◽  
Shell Effects ◽  
Internal Excitation ◽  
Classical Gas

The order-to-chaos transition in the dynamics of independent classical and quantum gas of particles was studied by means of the computer simulations within the nuclear model based on the time-dependent mean-field approach. The excitation of the classical gas for containers whose surfaces are rippled according to Legendre polynomials P2, P3 is followed for twenty periods of oscillations. For different vibration frequencies of small amplitude vibrations of such a container near the spherical equilibrium shape we obtained for the classical gas much smaller excitation energies than those predicted by the wall formula. With increasing equilibrium deformation they become significantly larger and for P3 vibrations they are close to the wall formula limit. Notable shell effects were found in the excitation energies of the quantum gas in the Woods-Saxon potential with the corresponding relatively sharp (diffuseness equals to 0.1 fm) moving surfaces for small-amplitude slow vibrations.

GROSS-SHELL EFFECTS IN THE DISSIPATIVE NUCLEAR DYNAMICS

2012 ◽  
Vol 21 (05) ◽  
pp. 1250034 ◽  
Author(s):  
J. P. BLOCKI ◽  
A. G. MAGNER ◽  
I. S. YATSYSHYN
Keyword(s):  
Collective Motion ◽  
Mean Field ◽  
Shell Correction ◽  
Nuclear Model ◽  
Quantum Gas ◽  
Excitation Energies ◽  
Nuclear Dynamics ◽  
Friction Coefficients ◽  
Periodic Orbit Theory ◽  
Shell Effects

The order-to-chaos transition in the dynamics of the quantum gas of independent particles was studied within the nuclear model based on the time-dependent mean-field approach. The excitation of the quantum gas in the Woods–Saxon potential with a small diffuseness of its surface rippled according to the Legendre polynomials P2 and P3 are obtained for a slow and small amplitude collective motion. We found strong correlations between time-derivatives of the excitation energies (one-body friction coefficients) and shell-correction energies as functions of the particle number. Semiclassical estimates of the friction coefficients were obtained within the periodic orbit theory by using the uniform approximation.

FISSION TIME OF α-INDUCED REACTIONS MEASURED BY THE CRYSTAL BLOCKING TECHNIQUE

2010 ◽  
Vol 19 (05n06) ◽  
pp. 1227-1235 ◽  
Author(s):  
V. A. DROZDOV ◽  
D. O. EREMENKO ◽  
O. V. FOTINA ◽  
S. Yu. PLATONOV ◽  
O. A. YUMINOV ◽  
...  
Keyword(s):  
Fission Fragment ◽  
Statistical Approach ◽  
Reliable Information ◽  
Fission Barrier ◽  
Large Set ◽  
Angular Anisotropy ◽  
Excitation Energies ◽  
Shell Effects ◽  
Pu Isotopes ◽  
Nuclear Dissipation

A large set of experimental observables for the 232 Th , 235 U (α, xnf ) reactions has been analyzed within the dynamic-statistical approach with allowance for the nuclear dissipation phenomenon, the double humped structure of fission barrier, and also the temperature damping of shell effects. The energy dependences of the lifetime effect (experimentally measured by the crystal blocking technique) along the corresponding data on the fission fragment angular anisotropy and also fission probabilities of U and Pu isotopes produced in the reactions were chosen for the analysis. Reliable information on the nuclear viscosity at the low excitation energies (< 30 MeV) was obtained.

scholarly journals Short-Time Photodissociation Dynamics of 1-Chloro-2-Iodoethane From Resonance Raman Spectroscopy

1999 ◽  
Vol 19 (1-4) ◽  
pp. 71-74 ◽  
Author(s):  
Xuming Zheng ◽  
David Lee Phillips
Keyword(s):  
Raman Spectroscopy ◽  
Absorption Spectrum ◽  
Raman Spectra ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Time Dependent ◽  
Internal Excitation ◽  
Band Absorption ◽  
Resonance Raman Spectra ◽  
Short Time

We have obtained A-band absorption resonance Raman spectra of 1-chloro-2- iodoethane in cyclohexane solution. We have done preliminary time-dependent wavepacket calculations to simulate the resonance Raman intensities and absorption spectrum in order to learn more about the short-time photodissociation dynamics. We compare our preliminary results for 1-chloro-2-iodoethane with previous resonance Raman results for iodoethane and find that there appears to be more motion along non- C—I stretch modes for 1-chloro-2-iodoethane than for iodoethane. This is consistent with results of TOF photofragment spectroscopy experiments which indicate much more internal excitation of the photoproducts from 1-chloro-2-iodoethane photodissociation than the photoproducts from iodoethane photodissociation.

Ion-surface scattering in the time-dependent mean-field approximation

1988 ◽  
Vol 199 (1-2) ◽  
pp. 132-140 ◽  
Author(s):  
K.J. Schafer ◽  
N.-H. Kwong ◽  
J.D. Garcia
Keyword(s):  
Mean Field ◽  
Field Approximation ◽  
Time Dependent ◽  
Surface Scattering ◽  
Mean Field Approximation

scholarly journals Low-Cost Molecular Excited States from a State-Averaged Resonating Hartree-Fock Approach

2019 ◽  
Author(s):  
Jacob Nite ◽  
Carlos A. Jimenez-Hoyos
Keyword(s):  
Excited States ◽  
Configuration Interaction ◽  
Low Cost ◽  
Computational Cost ◽  
Mean Field ◽  
Chem Phys ◽  
Spin Projection ◽  
Excitation Energies ◽  
Hartree Fock ◽  
Orbital Relaxation

Quantum chemistry methods that describe excited states on the same footing as the ground state are generally scarce. In previous work, Gill et al. (J. Phys. Chem. A 112, 13164 (2008)) and later Sundstrom and Head-Gordon (J. Chem. Phys. 140, 114103 (2014)) considered excited states resulting from a non-orthogonal configuration interaction (NOCI) on stationary solutions of the Hartree–Fock equations. We build upon those contributions and present the state-averaged resonating Hartree–Fock (sa-ResHF) method, which differs from NOCI in that spin-projection and orbital relaxation effects are incorporated from the onset. Our results in a set of small molecules (alanine, formaldehyde, acetaldehyde, acetone, formamide, and ethylene) suggest that sa-ResHF excitation energies are a notable improvement over configuration interaction singles (CIS), at a mean-field computational cost. The orbital relaxation in sa-ResHF, in the presence of a spin-projection operator, generally results in excitation energies that are closer to the experimental values than the corresponding NOCI ones.

scholarly journals Low-Cost Molecular Excited States from a State-Averaged Resonating Hartree-Fock Approach

2019 ◽  
Author(s):  
Jacob Nite ◽  
Carlos A. Jimenez-Hoyos
Keyword(s):  
Excited States ◽  
Configuration Interaction ◽  
Low Cost ◽  
Computational Cost ◽  
Mean Field ◽  
Chem Phys ◽  
Spin Projection ◽  
Excitation Energies ◽  
Hartree Fock ◽  
Orbital Relaxation

Quantum chemistry methods that describe excited states on the same footing as the ground state are generally scarce. In previous work, Gill et al. (J. Phys. Chem. A 112, 13164 (2008)) and later Sundstrom and Head-Gordon (J. Chem. Phys. 140, 114103 (2014)) considered excited states resulting from a non-orthogonal configuration interaction (NOCI) on stationary solutions of the Hartree–Fock equations. We build upon those contributions and present the state-averaged resonating Hartree–Fock (sa-ResHF) method, which differs from NOCI in that spin-projection and orbital relaxation effects are incorporated from the onset. Our results in a set of small molecules (alanine, formaldehyde, acetaldehyde, acetone, formamide, and ethylene) suggest that sa-ResHF excitation energies are a notable improvement over configuration interaction singles (CIS), at a mean-field computational cost. The orbital relaxation in sa-ResHF, in the presence of a spin-projection operator, generally results in excitation energies that are closer to the experimental values than the corresponding NOCI ones.

scholarly journals TEMPERATURE DEPENDENCE OF THE NUCLEAR ENERGY IN RELATIVISTIC MEAN-FIELD THEORY

2005 ◽  
Vol 14 (03) ◽  
pp. 505-511 ◽  
Author(s):  
B. NERLO-POMORSKA ◽  
K. POMORSKI ◽  
J. SYKUT ◽  
J. BARTEL
Keyword(s):  
Single Particle ◽  
Level Density ◽  
Mean Field Theory ◽  
Mean Field ◽  
Correction Method ◽  
Shell Correction ◽  
Shell Effects ◽  
Relativistic Mean Field ◽  
Single Particle Level ◽  
Particle Level

Self-consistent relativistic mean-field (RMF) calculations with the NL3 parameter set were performed for 171 spherical even-even nuclei with 16≤A≤224 at temperatures in the range 0≤T≤4 MeV . For this sample of nuclei single-particle level densities are determined by analyzing the data obtained for various temperatures. A new shell-correction method is used to evaluate shell effects at all temperatures. The single-particle level density is expressed as function of mass number A and relative isospin I and compared with previous estimates.

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