New modeling of germanium soft-X-ray lasers using extended atomic data

A collisional radiative model, explicitly including the interaction of the amplifying medium with the X-ray laser beam, is used to calculate the inten sity of the 2-1 and 0-1 lines in neon-like germanium, as well as the popula tion densities. The required energy levels and electron-impact collision st rengths involve the configurations 1s(2)2s(2)2p(6), 1s(2)2s(2)2p(5)3l, and 1s(2)2s2p(6)3l (l = s, p, d). The fine-structure excitation rates coefficie nts are presented for temperatures in the range 100-700 eV. Well-known nume rical codes are used for the atomic structure (SUPERSTRUCTURE) and electron -ion collisions (DISWAV/JAJOM). Finally, we solve the collisional radiative population equations. It is recommended to use excitation rates obtained f rom the extensive quantum calculations, rather than fit formulae. In this c ase, the calculated populations and intensities show substantial changes. ( C) 2000 Elsevier Science Ltd. All rights reserved.