The Influence of Foreign Gases on the Intensities of the Magnesium Resonance Lines 4571 And 2852

The Mg line 4571, $3{}_{}{}^1{}_{}{}^{}S-3\mathrm{}{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$, is very weak in the arc while 2852, $3{}_{}{}^1{}_{}{}^{}S-3\mathrm{}{}_{}{}^1{}_{}{}^{}P$, is very intense. The life of the $3{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ state is calculated to be 4×${10}^{-3\mathrm{}}$ sec., while $3{}_{}{}^1{}_{}{}^{}P$ has a life of 3×${10}^{-9\mathrm{}}$ sec. Collisions of second kind between excited Mg atoms reduce intensity of 4571 in the arc. At a vapor pressure of ${10}^{-4\mathrm{}}$ mm, the time between collisions of the Mg atoms is ${10}^{-3\mathrm{}}$ sec. The 4571 line should appear strong at this or lower vapor pressures. Vapor from solid Mg metal at 500°C was excited in an evacuated tube by an electrodeless short-wave discharge. The 4571 line appeared in the discharge as a fairly prominent line.