Calculation of ground- and excited-state energies of confined helium   atom
  We calculate the energies of ground and three low lying excited states of confined helium atom centered in an impenetrable spherical box. We perform the calculation by employing variational method with two-parameter variational forms for the correlated two-particle wave function. With just two variational parameters we get quite accurate results for both ground and excited state energies. 
Arup Banerjee, C. Kamal and Avijit Chowdhury