Electron impact excitation of fine-structure levels in Neon-like Krypton (Kr XXVII) using R-matrix method

Collision Strengths for transitions between the ground state and the lowest 26 fine-structure levels of Neon-like Krypton (Kr XXVII) are calculated us ing Breit-Pauli R-matrix method. The 27 fine-structure levels arising from the four lowest configurations 2s(2)2p(6), 2s(2)2p(5)3s, 2s(2)2p(5)3p, and 2s(2)2p(5)3d are included. Terms of the Breit-Pauli Hamiltonian are explici tly included in determining both the target and the scattering wavefunction s. All target levels included in the calculation are represented by configu ration interaction wave functions.: Our collision strengths are compared wi th the relativistic distorted-wave results of Reed. The excitation cross se ctions are integrated over a Maxwellian distribution of electron energies t o give electron excitation rate coefficients which are tabulated over a wid e range of temperatures from 600 eV to 2200 eV. The relative level populati ons for different electron densities and temperatures are also presented.