COMMENT ON DIFFERENTIAL CROSS-SECTIONS OF LOW-ENERGY ELECTRON-HYDROGEN SCATTERING IN A CO2-LASER FIELD

Cionga et al have employed the Kramers-Henneberger gauge when performi ng Floquet close-coupling calculations of electron-hydrogen scattering . It is shown that with their basis the effect of the laser on the tar get electron is described very inaccurately: their model assumes that the electron attached to the proton oscillates freely in the laser fie ld, whereas it is actually tightly bound for the laser intensities and frequencies considered. Such an effect could well explain the apparen t breakdown they observed of the Kroll-Watson low-frequency approximat ion.