AUTHOR=Dubovichenko S. B. , Yeleusheva B. M. , Burkova N. A. , Tkachenko A. S. 

TITLE=The reaction rate of radiative n8Li capture in the range from 0.01 to 10 T9

JOURNAL=Frontiers in Astronomy and Space Sciences

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2023.1251743

DOI=10.3389/fspas.2023.1251743

ISSN=2296-987X

ABSTRACT=<p>Within the modified potential cluster model (MPCM) with forbidden states, the total cross sections are calculated for capture in the ground and first excited states of the <sup>9</sup>Li nucleus in the <italic>n</italic><sup>8</sup>Li channel in the energy range from 10<sup>−5</sup> eV to 5 MeV based on <italic>Е</italic>1 and <italic>M</italic>1 transitions. The experimentally proved resonance at <italic>E</italic><sub><italic>c.m.</italic></sub> = 0.232 MeV in the <sup>4</sup><italic>P</italic><sub>5/2</sub> wave and <italic>ab initio</italic>-predicted <sup>4</sup><italic>P</italic><sub>3/2</sub> resonance at 1.32 MeV [Phys. Rev. C 103, 035801 (2021)] are considered. The strong impact of the asymptotic constant and channel spectroscopic factors on the total capture cross sections are responsible for the variation in the absolute values within factor two. As a consequence, the thermal cross sections are <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>σ</mml:mi><mml:mrow><mml:mi>t</mml:mi><mml:mi>h</mml:mi><mml:mi>e</mml:mi><mml:mi>r</mml:mi><mml:mi>m</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo></mml:mrow></mml:math></inline-formula> 24–46.8 mb. The evaluation of <inline-formula id="inf2"><mml:math id="m2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>σ</mml:mi><mml:mrow><mml:mi>t</mml:mi><mml:mi>h</mml:mi><mml:mi>e</mml:mi><mml:mi>r</mml:mi><mml:mi>m</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> based on the extrapolation of <italic>ab initio</italic> cross sections yields ∼85 mb. The reaction rate is calculated in the temperature range from 0.01 to 10 <italic>T</italic><sub>9</sub>. The reported reaction rates are compared at the benchmark point 1 <italic>T</italic><sub>9</sub>. The comparison of two datasets [Phys. Rev. C 103, 035801 (2021) and Phys. Rev. C 105, 064608 (2022)] on reaction rates recently calculated in microscopic models in extended temperature intervals shows the essential quantitative and qualitative differences. The comparative joint analysis of the reaction rates of radiative neutron capture on the lithium isotopes <sup>6,7,8</sup>Li is suggested for the choice of an optimal interval for the asymptotic constants.</p>