Some Characteristics of Time-Resolved Spectra

Some general observations made possible by time-resolved spectroscopy include the following. 

A continuum is produced at the beginning of the discharge. Its duration is directly proportional to the excitation energy. 

The periodicity of the spectral intensity of spark lines of high excitation levels varies with the current until they cease to radiate. 

Arc lines of lower excitation levels do not vary in intensity periodically. They may radiate after the spark discharge ceases. 

An intense periodicity occurs in the vicinity of the cathode, probably due to ejection of electrode sample into the gap. 

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