Optogalvanic spectroscopy has been applied to the measurement of the pressure broadening and frequency shift of the Ar 7d[5/2]3–4p[3/2]2 transition in the negative glow region of a hollow cathode discharge at gas pressures from 1 to 6 Torr and discharge currents from 12 to 20 mA. The neutral atoms have been found to be the dominant collision partners to the argon atoms in the excited state, and the values of β = (3.9 ± 0.2) × 10−3 cm−1 Torr and δ = −(3.9 ± 0.2) × 10−3 cm−1/Torr have been derived as the coefficients of the pressure broadening and shift, respectively.
Takashi Masaki, Yukio Adachi, and Chiaki Hirose, "Application of Optogalvanic Spectroscopy to the Measurement of Pressure Broadening and Shift in the Negative Glow Region of an Ar Hollow Cathode Discharge," Appl. Spectrosc. 42, 54-56 (1988)