Absolute excitation rate coefficients for Fe xvi and Ni xvi ions ions are measured spectroscopically in the Texas Experimental Tokamak. Previous measurements for the 3d-3p transition array of Cu xvii are verified and the measurements are extended to the 3s3$p^2$→3$s^2$3p transition array of this ion. The experimental rate coefficient for the 3d-3p transition array of Fe xiv is 6.2×${10}^{\mathrm{-}9}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{\mathrm{-}1}$ at an electron temperature near 160 eV and for Ni xvi and Cu xvii, the values are 4.2×${10}^{\mathrm{-}9}$ and 3.8×${10}^{\mathrm{-}9}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{\mathrm{-}1}$, respectively, at an electron temperature near 240 eV. For the 3s3$p^2$ ${}^2$$P_{3/2}$→3$s^2$3p ${}^2$$P_{3/2}$ transition array, the experimental excitation rate coefficient for Fe xiv is 8.2×${10}^{\mathrm{-}9}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{\mathrm{-}1}$ at an electron temperature near 160eV and for Ni xvi and Cu xvii the value is 5.5×${10}^{\mathrm{-}9}$ ${\mathrm{cm}}^3$ ${\mathrm{s}}^{\mathrm{-}1}$ at an electron temperature near 240 eV. The uncertainty in these results is estimated to be ±50% (one standard deviation). Computed values of absolute excitation rates in a distorted-wave approximation and Mewe’s semiempirical formula are found to be in good agreement with the experimental values.

• Received 21 July 1987

DOI:https://doi.org/10.1103/PhysRevA.36.5448