Excitation of the resonance levels of $Sr^+$ and $Ba^+$ ions in a discharge in a hollow cathode

The mechanism of excitation of resonance levels of strontium ions $5р^2Р_{3/2}$ and barium ions $6р^2Р_{3/2}$ in a discharge in a running-water-cooled hollow cathode with a helium filler is studied at $р=0.4\div 1.6$ mmHg and $i_р=100\div 400$ mA and with an argon filler at $р= 0.075\div 0.5$ mmHg and $i_p=50\div 200$ mA. It is established that in the investigated conditions the occupation of the resonance levels of the ions chiefly occurs due to collision between the electrons and the ions and atoms in the ground states and their depletion - primarily due to spontaneous transitions.