Determination of the effective radiative lifetime of the 6 3P1 atomic mercury level in low-pressure mercury discharges

Experiments are described in which low-pressure mercury, mercury-argon, and mercury-krypton discharges were irradiated with a dye laser pulse at 405 nm, thus exciting mercury atoms from the metastable 6 3P0 level to the 7 3S1 level. The 7 3S1 level decays radiatively to the 6 3P levels. By recording the time dependence of the 6 3P1 level density at the 254-nm fluorescence signal, the effective radiative lifetime of this level was determined. These measurements were performed for a wide range of mercury vapor densities. From the effective radiative lifetime and the 6 3P1 level density, the 254-nm output can be calculated. Reasonable agreement is found for two discharges of which the 254-nm output had been measured directly.