Abstract
Finite temperature results in various effects on the properties of nuclear structure and excitations of relevance
for nuclear processes in hot stellar environments. Here, we introduce the self-consistent finite temperature
relativistic quasiparticle random phase approximation (FT-RQRPA) based on relativistic energy density functional with point coupling interaction for describing the temperature effects in electric dipole (E1) transitions.
We perform a study of E1 excitations in the temperature range T = 0–2 MeV for the selected closed- and
open-shell nuclei ranging from 40Ca to 60Ca and 100Sn to 140Sn by including both thermal and pairing effects.
The isovector giant dipole resonance strength is slightly modified for the considered range of temperature,
while new low-energy peaks emerge for E < 12 MeV with non-negligible strength in neutron-rich nuclei
at high temperatures. The analysis of relevant two-quasiparticle configurations discloses how new excitation
channels open due to thermal unblocking of states at finite temperature. The study also examines the isospin and
temperature dependence of electric dipole polarizability (αD), resulting in systematic increase in the values of
αD with increasing temperature, with a more pronounced effect observed in neutron-rich nuclei. The FT-RQRPA
introduced in this work will open perspectives for microscopic calculation of γ -ray strength functions at finite
temperatures relevant for nuclear reaction studies.