The Quenching of Mercury Resonance Radiation (2537A) by Nitrogen

When a mercury atom in the resonance $6{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ state collides with a nitrogen molecule, it may be transferred to the metastable $6{}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}$ state. The cross section for this reaction has been measured by a new method. Mercury vapor, in the presence of a known pressure of nitrogen gas, is excited by 2537A radiation. After the source of the excitation is cut off, the decay time of the imprisoned radiation is observed. The quenching collision cross section ${\sigma }_Q$ is calculated from the measured decay time and the known value of the imprisonment time in the absence of the quenching gas. Measurements have been taken over the temperature range 325-525°K; ${\sigma }_Q$ is found to increase from 5.0×${10}^{-17\mathrm{}}$ ${\mathrm{cm}}^2$ at the lower temperature to 1.0×${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$ at the upper temperature.