The 1,3Po states of exponential cosine-screened heliumlike atoms

We investigate the singly-excited and doubly-excited 1,3Po states of screened-heliumlike atoms (Z=310), starting from Li+ to Ne8+ under the influence of exponential cosine-screened (ECS) Coulomb potentials. Pseudo-random-parameters dependent correlated exponential wave functions are used to represent the correlation effects between the charged particles. The singly-excited 1s2p 1,3P states are also estimated based on the Ritz variational method. The doubly excited resonance energies and widths are determined using the stabilization method. A total of 9 P-wave resonances including four members in the 2snp+ (2 < n < 5) series, three members in the 2snp-(3 < n < 5) series, and two members in the 2pnd (n = 3, 4) series for each screened-systems below the 2s 2S thresholds of the respective one-electron subsystems are reported. The singly-excited state energies for each system and each screening parameter below the n = 1 thresholds of the respective subsystems are also reported. The singly-excited states of ECS-heliumlike systems (Z = 6-10) and the doubly-excited 1,3Po states of the ECS-heliumlike systems are presented for the first time in the literature. (c) 2021 Elsevier Inc. All rights reserved.