RELATIVE INTENSITIES OF 3P-3S TRANSITIONS IN NEON-LIKE AR-IX

Argon was added in small amounts to theta-pinch discharges in hydrogen and deuterium, and the relative intensities of all 3p --> 3s transiti ons of neonlike argon were measured at the peak of the Ar IX concentra tion. At this time recombination was small since the ion was in an ion izing regime; effective excitation of the 3p levels was essentially du e to direct collisional excitation from the ground state and cascading contributions after excitation to higher levels. The relative intensi ties are compared with theoretical calculations, which employed variou s collisional and radiative transition rates given in the literature. Very good overall agreement is obtained with a collisional-radiative m odel which includes all levels up to n = 5.