A Guide to Helium

In this collection, the authors present a new theoretical approach free from limitations of perturbation theory for calculating atomic emission spectra in an alternating electric field. The following problems are studied for the emission spectrum of helium: dependences of the AC Stark effect, transition probabilities and spectral line intensities on the electric field parameters, reasons for the change in the emission color with increasing electric field frequency, mechanisms of a sudden increase in spectral line intensities, and their quenching in the electric field and mechanisms of the formation of spectral line profiles in the electric field. Next, the authors discuss the sampling and analytical procedure for helium in forensic practice. In cases of suspected helium exposure, the analysis of helium is commonly performed by the gas chromatography (GC) with thermal conductivity detector or gas chromatography-mass spectrometry (GC/MS) in combination with head-space (HS) method. A subs