Free energy and criticality in the nucleon pair breaking process

Abstract

Experimental level densities for 171,172Yb, 166,167Er, 161,162Dy, and 148,149Sm are analyzed within the microcanonical ensemble. In the even isotopes at excitation energies E < 2 MeV, the Helmholtz free energy F signals the transition from zero to two quasiparticles. For E > 2 MeV, the odd and even isotopes reveal a surprisingly constant F at a critical temperature Tc of appr. 0.5 MeV, indicating the continuous melting of nucleon Cooper pairs as function of excitation energy.

arXiv comment11 pages, including 6 figures, to be published in Physical Review C

References in corpus (10)

• Extraction of level density and gamma strength function from primary gamma spectra
• Critical temperature for quenching of pair correlations
• Gamma-ray strength function and pygmy resonance in rare earth nuclei
• Thermal and electromagnetic properties of 166-Er and 167-Er
• Level densities and $\gamma$-strength functions in ${}^{148,149}$Sm
• Entropy in hot ^{161,162}Dy and ^{171,172}Yb nuclei
• Entropy of thermal quasiparticles in nuclei
• Shell Model Monte Carlo Investigation of Rare Earth Nuclei
• Shape Transition in Rare-Earth Nuclei in Relativistic Mean Field Theory
• Shell model Monte Carlo calculations for Dy-170

Cited by in corpus (12)

• Thermal properties and radiative strengths in 160,161,162Dy
• Constant-temperature level densities in the quasi-continuum of Th and U isotopes
• Pairing transitions in the finite-temperature relativistic Hartree-Bogoliubov theory
• Level densities and $\gamma$-ray strength functions in ${}^{170,171,172}$Yb
• Thermodynamics of pairing in mesoscopic systems
• Thermodynamics of nuclei in thermal contact
• Evidence for the pair-breaking process in 116,117Sn
• Influence of complete energy sorting on the characteristics of the odd-even effect in fission-fragment element distributions
• Thermodynamics of pairing transition in hot nuclei
• Diagrammatic calculation of thermodynamical quantities in nuclear matter
• Neutron drip line of $Z=9-11$ isotopic chains
• Thermodynamics of pairing transition for Odd-A nuclei