The doubly-excited 2p^2 1D^eresonance state of the helium atom in hot-dense plasmas

Abstract

The 2p 2 1 D e resonance state of the helium atom embedded in model plasma environments is calculated using CI-type basis functions. The plasma effects have been taken care of by using the screened Coulomb potential obtained from the Debye model. The stabilization method has been used to extract resonance parameters. The resonance energy and width for the lowest 1 D e resonance for different screening parameters are reported.

Unnatural parity states of helium with screened Coulomb potentials

“…The results presented in Table I and Figure 1 are obtained using 1233‐terms for the singlet F‐states, 1160‐term for the triplet F‐states and 1296 terms for singlet and triplet G‐states. Convergence of the calculations using CI‐basis has been well‐discussed in our recent works 1, 3.…”

“…The nonrelativistic Hamiltonian H in Rydbergs units for helium atom embedded in Debye plasma is given by where λ D (μ = 1/λ D , the Debye screening parameters) is the Debye lengths for the electron‐nucleus and electron‐electron screening, r 1 and r 2 are the radial coordinates of the two electrons and r 12 is their relative distance. As in our earlier works 1–3, here, we have included the electron‐nucleus screening explicitly, but approximated the electron‐electron screened Coulomb potential by …”

“…Comparing our earlier results 3, 22 on the bound D‐states using correlated exponential basis functions 22 with those using the CI‐type basis functions (3) 3, it was observed that the CI‐type basis led to reasonably accurate results as those obtained using the correlated exponential basis functions 22. It was observed in out earlier study 1–3 that the convergence of the 1 P e and 1 D e resonance state of helium in plasmas for different Debye lengths using the CI‐type basis sets is quite good. With the above observations, we believe that using the CI‐type basis sets (4) with the proposed approximations will also give reasonably accurate results for the 1,3 D o , 1,3 F e , and 1,3 G o resonance states of He atom immersed in plasmas for Debye lengths up to λ D ≈ 10, corresponding to μ = 1/λ D = 0.1.…”

“…Results are obtained using CI‐type basis functions. Recently, we have calculated the meta‐stable bound P‐, D‐states 1, 2 and the P‐wave resonance states 1 with unnatural parity, and D‐wave resonance states 3 with natural parities using CI‐type basis sets for the plasma‐embedded He atom. We have also reported the S‐, P‐, D‐waves resonances with natural parities of π = (–1) L for the plasma‐embedded He atom 3–8.…”

Calculations of D‐wave bound states and resonance states of the screened helium atom using correlated exponential wave functions

“…Effects of screening on the atomic processes has gained considerable attention in the recent years (1–14 references therein). Screened Coulomb (Yukawa‐type) potentials were employed in the recent studies to represent the interaction between the charged particles in the Hamiltonian.…”