Multiple ionization of diethyl ether cluster by nanosecond laser: generation of multiply charged ions and the electron energy distribution

Abstract

The interaction of diethyl ether clusters and laser was studied at laser intensity of 1011 W/cm2 using 5 ns, 1064 nm laser pulses. Multiply charged ions O6+ and C4+ were observed and the ratio of O6+/C4+ nearly kept constant in the range of laser intensity studied. The energy distribution of electrons ejected was measured via retarding potential method. At the laser intensity of 4.0×1011 W/cm2, the mean electron energy of 56eV and the maximum electron energy of 102eV were observed. It indicates that the multiply charged ions are mainly produced from energetic electron impact ionization. In addition, our calculated results show that the screening effect inside cluster can significantly decrease the ionization potentials of multiply charged ions, thus facilitating the ionization especially at low laser intensity. The above results further support our three stage model of “multiphoton ionization ignition-inverse bremsstrahlung heating-electron impact ionization”.