Electron-impact excitation of the level in ytterbium

Abstract

We have measured and calculated differential cross sections for electron-impact excitation of the . . . 6s6p 1 P 1 level in ytterbium at collision energies of 5, 10, 20, 40 and 80 eV. Calculations were made in the unitarized distorted-wave approximation. Measurements of the relative differential cross section, taking account of volume correction effects, were placed on an absolute scale by normalization to the theoretical integral cross section at 80 eV with extrapolation to lower energies based on the measured excitation function of Shimon et al (1981 Opt. Spektrosk. 50 571). Excellent agreement between theory and experiment is obtained in the regime of low momentum transfer.

Radiative Losses of Solar Coronal Plasmas

“…For example, for electron-impact excitation, our calculations have been compared with other calculations and experimental measurements for a variety of atoms and ions, including Mg, Ba, Xe, Ne, and Ar (Clark et al 1989(Clark et al , 1991b(Clark et al , 1992Khakoo et al 1996;Zetner et al 1997;Baerveldt et al 1998;Johnson et al 1998;Fursa et al 1999Fursa et al , 2002Zetner et al 2001;Meneses et al 2002). For electron-impact ionization, recent calculations using the Los Alamos codes have been shown to be in good agreement with the experiment for inner shell ionization of heavy atoms (Colgan et al 2006b) and for many of the ions of Si and Ar (Colgan et al 2008).…”

Differential cross sections for electron-impact excitation of laser-excited174Yb (…6s6p 3P1)

“…Earlier experimental studies of ground state electron scattering include optical excitation functions from Shimon et al [4] and relative differential cross sections by Kazakov and Khristoforov [5]. Ground state inelastic studies include the absolute differential cross section for excitation of the 1 P 1 state [6] and the 3 P 1 state [7]. More recently, Predojević et al have studied elastic and inelastic scattering from ground state ytterbium [8,9].…”

“…Relativistic distorted-wave (RDW) approximation calculations of Srivastava et al [10] report differential cross sections, electron-impact coherence parameters (EICP) and spin parameters for these transitions. Unitarized distorted-wave (UDW) approximation calculations [6,7] report differential and integral cross sections for these transitions.…”

“…The cross sections were measured relative to ground state inelastic transitions, producing relative polarization-averaged partial differential cross sections. To present absolute cross sections for the features in this study, the absolute differential cross sections from [6] and [7] were used, renormalized to present RCCC theory. This process is described in section 6.2.…”

Electron collisions by metal atom vapours

“…transition 4f 14 ð 1 SÞ6s 2 1 S 0 ! 4f 14 ð 1 SÞ6s6p 1 P 1 at 399 nm (3.108 eV), received a substantial interest in the recent years as it is widely used in laser cooling experiments (Rapol et al, 2004), absolute frequency measurements (Das et al, 2005) and electron scattering (Johnson et al, 1998;Predojevicé t al., 2005). Extensive calculations for excitation parameters of all fine structure levels of the 6s6p states of Yb are presented by Srivastava et al (1995).…”