High-resolution measurement of electron excitation to the 4S states of helium
D W O Heddle; R G W Keesing; D W O Heddle; Department of Physics, University of York, Heslington, Yorks.; R G W Keesing; Department of Physics, University of York, Heslington, Yorks.
Журнал:
Proceedings of the Physical Society
Дата:
1967-06-01
Аннотация:
We have made a hemispherical electron monochromator and measured the optical excitation functions of the 4 <sup>1</sup>S and 4 <sup>3</sup>S states of helium close to threshold. Both excitation functions reach a significant value within 30 mV of threshold and show two narrow maxima. The second maxima coincide in energy (between 23.77 and 23.80 eV) and are identified with a resonance having the configuration (1s5s<sup>2</sup>)<sup>2</sup>S<sub>1/2</sub>.
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