Concerning the possibility of radiative decay of the collective levels of the argon atom
Verkhovtseva E.T., Pogrebnyak P.S., Fogel' Ya.M.
The x-ray spectrum of Ar in the 15-200 A region was investigated with an aim at detecting the radiation of the collective vibrations of the electron shell of the atoms. No collective-vibration radiation was observed, possibly either because of the insufficient number of electrons in the Ar-atom shell or because of the low probability of the radiative decay of its collective levels.