Ionization processes in fluorescent lamps: evaluation of the Hg chemi-ionization rate coefficients.

Chemi-ionization by two mercury atoms to produce mercury atomic and molecular ions has been considered an important process in fluorescent lamps (FLs) for a quarter of a century. Despite the absence of reliable data, these processes have been included in a number of numerical models to help explain some of the experimental observations. These models have shown that the most important process is the Penning ionization of two Hg metastable atoms Hg(6(3)P2)+Hg(6(3)P2) --> Hg(+)+Hg(6(1)S0)+e.