Atomic transition probabilities and tests of the spectroscopic coupling scheme for N i

With a wall-stabilized arc source, we have measured the relative transition probabilities of 100 lines of neutral nitrogen in the visible and near-infrared spectrum and have normalized our data to an absolute scale utilizing four recent lifetime results. We estimate that the expanded uncertainties of our data are in the range of ±11–15 %. For a number of 3s-3p and 3p-3d multiplets, we have measured complete sets of lines and observe that most 3p-3d multiplets show considerable departure from LS coupling, while the 3s-3p multiplets adhere to it within ±20%. Agreement between intermediate coupling calculations and our experimental data for the 3p-3d multiplets is noticeably better, but significant differences are still encountered for two multiplets originating from the 3d ${}_{}{}^4{}_{}{}^{}$P level.