Electron excitation out of the metastable level of He into high-ntriplet levels

Abstract

We report cross section results for electron excitation out of the 2 3 S metastable level of He into the 5 3 P, 6

Precision calculation of low-energy electron-impact excitation cross sections of helium among the ground and excited states

“…The available experimental measurements shown in Fig. 8 are from Piech et al [18,19]. We have subtracted the cascade contribution from the exper imental measurements using our calculated high-excitation cross sections.…”

“…For the absolute measurement experiment, the state-of-theart experimental precisions are anticipated with only about 10% [17]. For example, absolute measurements of the cross sections (Piech et al [18,19]) often lead to considerable un certainties, sometimes the uncertainties were even larger than the measured quantities. Therefore, theoretical computations should play an indispensable role to satisfy needs.…”

“…This demonstrates that our high-excitation scattering cross sections are also in good quality, which should be useful for the related applications and will be reported elsewhere. For the excitation processes from the excited states, the absolute measurement data of Piech et al [18,19] provide transitions from the [ls2s] 2 3S, but with large uncertainties. As high-resolution measurement of cross sections from lower-excitation states are limited, how to estimate the precision of the calculation from a lower-excitation state is still a difficult problem.…”

Measurement of Cross Sections for Electron Excitation out of the Metastable Levels of Argon

“…The few measurements performed on metastable argon include cross section measurements of total electron scattering [8], ionization [9], and excitation [10,11]. Measurements of electron excitation cross sections out of the metastable levels of He exhibit numerous unexpected effects of fundamental interest [12,13]. The results reported in this Letter for excitation of metastable Ar will enable a more thorough understanding of electron-metastable atom collisions.…”

“…The electron excitation cross sections for the other 2p levels are obtained by taking the ratio of their fluorescence signals to that of the 2p 9 level. We utilize the ground level signals and cross sections to determine the optical efficiency of the apparatus at different wavelengths, as described by Piech et al [12,13]. In this way we obtain absolute apparent electron excitation cross sections for the other 2p levels.…”