Classification of X-Ray Spectra from Laser Produced Plasmas of Atoms from Tm to Pt in the Range 6-9 Å

X-ray spectra of highly ionized tungsten and neighbouring atoms (Tm, Yb, Hf, Ta, W, Re and Pt) has been observed from laser produced plasmas in the λ = 6-9 A range. Beside the prominent lines of the Ni I-like ions, lines belonging to Co I (3d ⁹-3d ⁸4p), Cu I (3d ¹⁰4s-3d ⁹4s4p, 3d ¹⁰4p-3d ⁹4p ²) and Zn I-like ions (3d ¹⁰4s ²-3d ⁹4s ²4p, 3d ¹⁰4s4p-3d ⁹4s4p ²) have been identified. Classification was based on isoelectronic sequence analysis and on comparison with ab-initio relativistic calculations. A collisional-radiative model of the Cu I-like ions in the plasma is used to show that the contribution of the 3d ¹⁰4d-3d ⁹4p4d and 3d ¹⁰4f-3d ⁹4f4p transition arrays to the 3d-4p spectrum is small. The importance of configuration interaction is pointed out. Computations agree with measurements within experimental uncertainty.