Non-sequential double ionization of diatomic molecules: alignment dependence of electron correlation

We study the electron momentum correlation of an aligned diatomic molecule using a semiclassical model that includes tunnelling ionization and consequent depletion of excited states in the non-sequential double ionization (NSDI) process. The electron correlation distribution shows an alignment dependence. Our analysis shows that this alignment effect can be attributed to alignment-dependent ionization of the excited states involved in the NSDI process.