Transition probabilities of several transitions in the ArIII and ArIV spectra

Using the relative line intensity ratios method between transitions that be long to the same multiplet in the Ar III (4s - 4p. 4s' - 4p' and 4p' - 4d' transitions) and Ar IV (4s - 4p and 4s' - 4p' transitions) spectra, some of the existing transition probability values (A) have been controlled. On th e basis of the confirmed A values in Ar III (328.585 nm, 330.188 nm, 331.12 5 nm, 333.613 nm and 334.472 nm) and in Ar IV (280.944 nm and 278.896 nm) s pectra two A values in Ar III and seven A values in Ar IV spectra have been determined, for the first time, relatively to the confirmed A values. Besi de, some of the existing theoretical A data have been corrected, according to our experimentally observed relative line intensity ratio values. Measur ements have been performed by using the linear low pressure pulsed arc, as an optically thin plasma source, operated in argon-helium mixture.