Non-sequential double ionization of triatomic molecules OCS in intense laser fields

[Display omitted] •Investigating the NSDI yield of OCS molecule in experimentally and theoretically.•Analyzing different mechanisms by calculating the momentum distribution.•The mechanisms are demonstrated by the energy and corresponding trajectories.•The energy transfer in a collision process also depends on the impact parameter. We investigated the non-sequential double ionization of the OCS molecule at both 800 nm and 1200 nm laser fields. For the double ionization with different laser wavelengths, an alternating high and low yields were observed in the yields dependence on the laser intensity. To get insight of this phenomenon, the mechanisms of the strong field double ionization were analyzed in details. An abnormal change of the mechanism was identified at 1200 nm laser fields as the laser intensity increases. With further discussions, the influence of laser wavelength on the NSDI was studied.