The variational Monte Carlo method is employed to conduct a comprehensive investigation of the compressed ground and excited states of plasma-embedded lithium atom within impenetrable spherical boxes of varying radii. The study focuses on the low-lying excited doublet states 1 \(s^{{2}}\) ns, 1 \(s^{{2}}n\) p, and 1 \(s^{{2}}n\) d, utilizing plasma potentials such as the screened Coulomb (SCP), exponential cosine screened Coulomb (ECSCP), and Hulthén potentials. Energy eigenvalues are determined using appropriate trial wave functions, which account for electron–electron repulsion and spin parts to adhere to the Pauli Exclusion Principle. Moreover, two factors related to the wave function of the compressed system and ECSCP model are considered. The results reveal an intriguing relative ordering for the lithium atom using the three plasma models, with many of the findings being significant contributions yet to be explored.
