Study of compressed beryllium atom embedded in various screening plasma potentials: ground and low-lying excited singlet and triplet states

The variational Monte Carlo method is employed to conduct a new comprehensive investigation of the compressed ground and excited states of plasma-embedded beryllium atom within impenetrable spherical boxes of varying radii. The study focuses on the low-lying excited singlet and triplet states (1s22s2p, 1s22p2, 1s22s3s, and 1s22s3p), utilizing plasma potentials such as the screened Coulomb (SCP), exponential cosine screened Coulomb (ECSCP), and Hulth & eacute;n 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 beryllium atom using the three plasma models, with many of the findings being novel contributions yet to be explored.