Photoionization of helium from the excited state 4p1P1
Belik V.P. , Bobashev S.V. , Shmaenok L.A.
The cross section for the photoionization of helium from the excited state Α ρ ιΡλ by radiation of wavelength 1.06 μηι is experimentally found to be cr = (3.9±1.5)XlO-18 cm2.