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We present multi-configuration Breit-Pauli distorted-wave photoionization(PI) cross sections and radiative recombination (RR) and dielectronicrecombination (DR) rate coefficients for the first six krypton ions. These werecalculated with the AUTOSTRUCTURE code, using semi-relativistic radialwavefunctions in intermediate coupling. Kr has been detected in severalplanetary nebulae (PNe) and H II regions, and is a useful tracer ofneutron-capture nucleosynthesis. PI, RR, and DR data are required to accuratelycorrect for unobserved Kr ions in ionized nebulae, and hence to determineelemental Kr abundances. PI cross sections have been determined for groundconfiguration states of Kr^0--Kr^5+ up to 100 Rydbergs. Our Kr^+ PIcalculations were significantly improved through comparison with experimentalmeasurements. RR and DR rate coefficients were determined from the direct andresonant PI cross sections at temperatures (10^1--10^7)z^2 K, where z is thecharge. We account for Delta n=0 DR core excitations, and find that DR is thedominant recombination mechanism for all but Kr^+ at photoionized plasmatemperatures. Internal uncertainties are estimated by comparing resultscomputed with three different configuration-interaction expansions for eachion, and by testing the sensitivity to variations in the orbital radial scalingparameters. The PI cross sections are generally uncertain by 30-50% near theground state thresholds. Near 10^4 K, the RR rate coefficients are typicallyuncertain by <10%, while those of DR exhibit uncertainties of factors of 2 to3, due to the unknown energies of near-threshold autoionizing resonances. Withthe charge transfer rate coefficients presented in the third paper of thisseries, these data enable robust Kr abundance determinations in photoionizednebulae for the first time.

Atomic data for neutron-capture elements II. Photoionization and recombination properties of low-charge krypton ions