The allowed charge-changing transitions are the
most common weak interaction processes of spin-isospin
form that play a crucial role in several nuclear/astrophysical
processes. The first-forbidden (FF) transition becomes im-
portant, in the circumstances where allowed Gamow-Teller
(GT) transitions are unfavored, specifically for neutron-rich
nuclei due to phase space considerations. In this paper de-
formed proton-neutron quasi-particle random phase approx-
imation (pn-QRPA) model is applied, for the first time, for
the estimation of allowed GT and unique first-forbidden
(U1F) transitions (|J | = 2) of neutron rich copper iso-
topes in mass range 72 ≤ A ≤ 82 under stellar conditions.
We compared our computed terrestrial β-decay half-life val-
ues with previous calculations and experimental results. It
was concluded that the pn-QRPA calculation is in good ac-
cordance with measured data. Our study suggests that the
addition of rank (0 and 1) operators in FF transitions can
further improve the comparison which remain unattended
at this stage. The deformed pn-QRPA model was employed
for the estimation of GT and U1F stellar electron emis-
sion (β − -decay) rates over wide range of stellar temper-
ature (0.01 GK–30 GK) and density (10–10 11 g/cm 3 ) do-
mains for astrophysical applications. Our study shows that,
in high density and low temperature regions, the contribu-
tion of U1F rates to total electron emission rates of neutron-
rich copper nuclei is negligible.

EB00000003868K

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• Allowed and unique first-forbidden stellar electron emission rates of neutron-rich copper isotopes