Alignment-dependent ionization of nonlinear triatomic molecules in strong laser fields

Abstract

The alignment- and channel-resolved ionization of the triatomic nonlinear molecules SO2 and H2O in strong fields has been studied using the strong-field approximation theory. When the instantaneous electric field points from O to S in SO2 or from H to O in H2O, the ionization rate is much larger than in the opposite case. The antibonding nature and destructive interference of the electron wave packets with opposite phases lead to distinct ionization suppression on the highest occupied molecular orbital (HOMO) of H2O and HOMO-1 of SO2. By controlling the relative intensity of the two-color 800 and 400 nm laser fields, the orientation-dependent ionization rate can be manipulated, and the electrons emitted from the different molecular orbitals can be disentangled in space. The orientation- and molecular-orbital-resolved ionization can be used to retrieve the complex structure of molecules to image the molecular orbitals HOMO, HOMO-1, and HOMO-2 as well as to steer the photoelectron emission of the laser-driven nonlinear molecules.