Practice of Kinetics (Comprehensive Chemical Kinetics, Volume 1)

3 APPARATUS 39than for singlet-singlet transitions. The lower excited states for mercury are shownin Fig. 27. Immediately above the ground state there are three triplet and onesinglet P states. Above these are the (6s7s)'S0, ( 6~7~)~s~ and (6~7d)~D, states.The 1849A and 2537A lines are resonance radiations since they appear in absorptionfrom, and emission to, the ground state. Double excitation occurs from the Pstates giving rise to lines such as 3130A, 3662A and 4358A.Low-pressure lumps. These lamps operate at or close to room temperature.This means that the vapour pressure of Hg is - torr. In addition tomercuryabout 6 torr of inert gas, usually neon, is added. This makes for easy firing butthere is some evidence that a higher intensity is produced due to reaction (13).Ne*+Hg('S,) --f Ne+Hg(3P,) (13)IIClampICReferences pp. 104-1 1 I" ter -L-4 Lightbaff Le