Statistics and characteristics of xuv transition arrays from laser-produced plasmas of the elements tin through iodine

Abstract

Spectra of laser-produced plasmas of the elements from tin to iodine contain weak bands of quasicon-0 tinuum overlaid by weak emission lines in the 70 -120-A region. Multiconfiguration-Dirac-Fock calculations show that these features are consistent with theoretical spectra for 4d 4d -'(Sf +6p) transitions in a number of adjacent ion stages which are predicted to produce unresolved transition arrays (UTA) in this spectral region. Moreover, the calculations predict a gradual decrease of 4d 5f osc-illator strength with increasing ionization up to the eleventh spectrum where ggf(4d 5f) =0.-However, inclusion of configuration interaction effects between the 4d'nf levels showed that 4d'4f and 4d~5f mixing shifts this minimum to the thirteenth spectrum. The theoretical data were then parametrized within the UTA formalism and the different order moments corresponding to weighted mean energy, variance, and skewness coefficient evaluated. PACS number(s): 32.70.n, 31.20.d, 32.30.Jc gress [16]. In this work we show that the weak emission bands observed in the vuv at A. &100 A are consistent with unresolved transition arrays of this type.

Opacity Effect on Extreme Ultraviolet Radiation from Laser-Produced Tin Plasmas

“…The dash-dotted, dashed, and dotted lines represent the spectra calculated by an atomic code HULLAC [14] with electron temperatures of 20.9, 31.0, and 40.3 eV, respectively. The configuration interaction between the 4d n , 4d nÿ1 4f, 4d nÿ1 5p, 4d nÿ1 5f, and 4p 5 4d n configurations were taken into account, since the configuration interaction changes the wavelength and strength of emission lines considerably [15]. The population of the ionization state was calculated under the collisional radiative equilibrium condition.…”

The atomic model of the Sn plasmas for the EUV source

“…In the case of these 4d ions, strong configuration mixing takes place between 4d i-1 4f and 4p 5 4d i+1 configurations, so that predominant emission is obtained at =13.5nm, because a large number of 4d-4f and 4p-4d fine structure transitions overwrap each other in a same wavelength region [2]. Ions beyond Kr-like state still have intense emission near =13.5nm through 4p-4d transitions, therefore Sn is an efficient emitter over a wide range of plasma temperature.…”

Steady-State and Time-Dependent LPP Modeling

“…The non-centred moments can be expressed in terms of the energy E i (or wavelength, λ i ) and weighted oscillator strength, gf i , for each line i (Svendsen & O'Sullivan, 1994) (Eq. 4).…”