A mechanism of two-electron multiphoton ionization of atoms
Delone N.B. , Zon B.A. , Krainov V.P. , Preobrazhenskii M.A.
A mechanism for the formation of doubly-charged ions, which were observed experimentally in the multiphoton ionization of a number of atoms, is proposed.111 This mechanism is based on the diffusive ionization of excited atoms/21 which in this case is realized in the optical frequency range.