  Theoretically self-consistent calculations for photoionization and (e + ion)
recombination are described. An identical eigenfunction expansion for the ion
is employed in coupled channel calculations for both processes, thus ensuring
consistently accurate cross sections and rates in an ab initio manner. The
theoretical treatment of (e + ion) recombination subsumes both the non-resonant
recombination ('radiative recombination'), and the resonant recombination
('di-electronic recombination') processes in a unified scheme. In addition to
the total, unified recombination rates, level-specific recombination rates and
photoionization cross sections are obtained for a large number of atomic
levels. Both relativistic Breit-Pauli, and non-relativistic LS coupling,
calculations are carried out in the close coupling approximation using the
R-matrix method. Although the calculations are computationally intensive, they
yield nearly all photoionization and recombination parameters needed for
astrophysical photoionization models with higher precision than hitherto
possible, estimated at about 10-20 % from comparison with experimentally
available data (including 'experimentally derived DR rates'). Results are
electronically available for over 40 atoms and ions. Photoionization and
recombination of He-, and Li-like C and Fe are described for X-ray modeling.
The unified method yields total and complete (e+ion) recombination rate
coeffcients, that can not otherwise be obtained theoretically or
experimentally. "temp" 23 lines, 1524 characters

Astrophysics;Atomic Physics