Electron–ion recombination rate constants in gaseous and liquid krypton

Electron drift mobilities μe and electron–ion recombination rate constants kr have been measured by the analysis of transient current induced with the irradiation of an x-ray pulse on gaseous or liquid krypton in a cell as a function of external electric field strength. The effects of an external dc electric field on kr up to 12 mTd (1 Td=10−17 V cm2/molecule) in liquid and 63 mTd in gas have been examined. The observed kr values in both liquid and gas phases have been found to be much smaller than those calculated by the reduced Debye equation. The deviation has been compared with recent theoretical studies, leading to the conclusion that recombination in liquid and gaseous krypton is not the usual diffusion-controlled reaction. The kr values in the gas phase increase with an external dc electric field up to a critical electric field strength below which μe values are nearly constant, and above which both kr and μe values descrease with further increase in the electric field for both gaseous and liquid phases.