Electron impact differential and integral cross sections for excitation of the n = 2 states of helium at 29.2 eV, 39.2 eV and 48.2 eV

Abstract

A high resolution electron impact spectrometer using electrostatic monochromators and the cross-beam technique is described. Considerations related to its construction and use in measuring cross-sections are discussed. This instrument has been used to obtain absolute values for differential and integral excitation cross-sections of the n = 2 manifold states of helium at 29.2 eV, 39.2 eV and 48.2 eV. The observations are presented and compared with currently available theoretical calculations

Uncertainty estimates for theoretical atomic and molecular data

“…Cross [188][189][190] are compared with predictions from nonrelativistic CCC [191] and RMPS [192] [193]). Figure 5 is an example of a systematic study regarding the convergence of the closecoupling expansion [193].…”

Electron Scattering by Atoms, Ions, and Molecules

“…The theoretical curves are from: RMPS, Bartschat et al (1996a); CCC, Fursa and Bray (1995); DWBA, Beijers et al (1987). The sources for the experimental data are: Hall et al (1973); Cartwright et al (1992); Eminyan et al (1974); Beijers et al (1987);McAdams et al (1980); Khakoo et al (1986).…”

Pattern Resolution in X-ray Lithography Using Pattern Replication Technique on a Mask

“…The DCS n=2 (90) values derived from the present TOF measurements and the associated error limits are also summarized in table 1. This table also contains DCS n=2 (90) values obtained from conventional energy-loss spectra measured by Hall et al (1973), Allan (1992), Cartwright et al (1992), and Trajmar et al (1992) as well as theoretical results from the FOMBT calculations of Cartwright et al (1992) and Trajmar et al (1992), the 29-state R-matrix calculations of Fon et al (1995) and the completely converged close coupling (CCC) calculations of Fursa and Bray (1995). For completeness the elastic DCS values used in the present work and obtained by interpolations from the measurements of Register et al (1980) are also given in table 1.…”