Relative Intensities of Some Lines in the Mercury Spectrum

Intensities of the most intense spectrum lines associated with transitions to and from the $2p_2$ state in mercury were measured by means of a photographic method. The spectrum of the vapor was excited by electron impact above the ionization potential. Variations in the line intensities due to changes in the accelerating potentials and vapor pressures were observed. At 22°C and with 50 volt electrons, there were about 1.7×${10}^{12}$ quanta of $\lambda 2537$ radiation emitted per cubic centimeter per second for a current density of 4.75×${10}^{15}$ electrons per square centimeter per second. From the intensities of the other lines relative to $\lambda 2537$, it was found that there are apparently more transitions to $2p_2$ than down from $2p_2$, as given by measurements of the radiation. This made it impossible to determine the probability of excitation of resonance from the intensities of the spectrum lines. A comparison is made between the relative intensities in the experimental tube and in a commercial arc.