A collisional-radiative (C-R) model for krypton plasma using fully relativistic distortedwave cross sections for electron excitations was developed. The model was applied to the characterization of inductively coupled Kr plasma with cylindrical geometry over the pressure regime 1-50 mTorr. Radially averaged emission intensities from transitions of Kr (4p 5 5p → 4p 5 5s) in the range 500-900 nm were recorded at 17 cm from the planar RF-driven coil, with the plasma operated in the inductive regime (H mode). The measured emission intensities were then fitted by varying the electron density, n e , and electron temperature, T e , in the C-R model. At both low and high pressures, variations of the electron density by over two orders of magnitude had only a minor role on the relative emission intensities. On the other hand, T e values deduced from the comparison between experiment and model decreased from 6.7 to 2.6 eV as pressure increased from 1 to 50 mTorr. These results are found to be in good agreement with the effective electron temperature determined from Langmuir probe measurements and the predictions of a model based on the particle balance equation of charged particles.

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Electron impact excitations from ground state L shell viz. n = 2 → n = 3 transitions in Mg-like W62+, Na-like W63+, Ne-like W64+, F-like W65+ and O-like W66+ ions have been considered. A fully relativistic distorted wave (RDW) theory has been used to calculate the excitation cross-sections for an electric and magnetic dipole, as well as for the quadrupole transitions for these ions, which were observed recently in the measurements taken from an electron-beam-ion trap (EBIT-I) at the Livermore laboratory. We have performed calculations in the electron impact energy range from a threshold excitation energy of up to 60 keV. Our results, where possible, have been compared with the few previous theoretical calculations that are available. Analytic fits to our calculated excitation cross-sections have also been done for plasma modeling purposes. Our calculated cross-sections have been further employed to obtain the linear polarization of the photon emissions for dipole-allowed transitions due to the decay of the electron impact excited anisotropic states to the ground state for all five of the tungsten ions that are considered in the present work.

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Accurate extreme ultraviolet spectra of open N-shell neodymium (Nd) ions were recorded at the electron beam ion trap facility of the National Institute of Standards and Technology. The measurements were performed for nominal electron beam energies in the range of 0.90 keV to 2.31 keV. The measured spectra were then compared with the spectra simulated by a collisional-radiative model utilizing atomic data produced with a fully relativistic atomic structure code. Consequently, 59 lines from Br-like to Ni-like Nd ions were unambiguously identified, most of which were newly assigned in this study. The wavelengths of 9 known lines from Ni-, Cu- and Zn-like Nd ions were in excellent agreement with previous measurements.

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