Experimental determination of line-intensity ratios of transitions within then=2complex of Be i–like ions (Cl xiv to Cr xxi)

The n=2 to n=2 transition lines in the Be i ion sequence of moderately-high-Z elements (Cl to Cr) were studied in the emission spectra of the Texas Experimental tokamak plasma when the appropriate elements were injected. A number of lines were identified for the first time. The relative brightnesses of the spectral lines were measured by an instrument with a photoelectric detector which was photometrically calibrated against synchrotron radiation. The brightness ratios of the 2s2p ${}^3$ $P_2$–2$p^2$ ${}^3$ $P_2$ (R) and the 2$s^2$ ${}^1$ $S_0$–2s2p ${}^3$ $P_1$ ($R^{\mathrm{*}}$) transitions to the resonance 2$s^2$ ${}^1$ $S_0$–2s2p ${}^1$ $P_1$ line were determined and compared with theoretical predictions. For R, the ratio of the experimental to the theoretical values was 1.01±0.19 and for $R^{\mathrm{*}}$, 0.84±0.17, indicating a good agreement with the calculations of relative level populations using collision strengths computed by the distorted-wave approximation.