Measurement of Transition Probabilities in the Visible Spectra of O I and C I and Estimation of Vacuum Ultra-violet Radiation Standards

Previously measured lines λλ3947, 4368, 5330, 5436 of O I and 4770, 4932, 5040, 5052, 5380 Å of C I have been remeasured using vortex arc methods. The new recommended transition probabilities in sec -1 × 10 5 are, for O I, 3.29, 8.57, 19.6, 29.4 and for C I 9.9, 32, 2.2, 12.6, 10.5 respectively. An axial temperature of 12 436 °K is found for a 50 amp, 8 mm diameter, water vortex arc. The absolute radiation from this arc is computed for Lyman α and O I λ 1302 Å to be 4.88 × 10 5 and 7.47 × 10 5 ergs sec -1 cm -2 sterad -1 (cm -1 ) -1 near the line centres respectively.