Strong-field ionization of water. II. Electronic and nuclear dynamics en route to double ionization

We investigate the role of nuclear motion and strong-field-induced electronic couplings during double ionization deuterated water using momentum-resolved coincidence spectroscopy. By examining three-body dicationic dissociation channel, D$^{+}$/D$^{+}$/O, for both few- multi-cycle laser pulses, strong evidence intra-pulse dynamics is observed. The extracted angle- energy-resolved yields are compared to classical trajectory simulations occurring from different states dication. In contrast with measurements single photon ionization, pronounced departure expectations vertical observed, even pulses as short 10~fs in duration. outline numerous mechanisms by which field can modify wavefunction en-route final dication where molecular fragmentation occurs. Specifically, we consider possibility a coordinate-dependence strong-field rate, intermediate monocation prior near-resonant laser-induced dipole ion. These results highlight fact that, small light molecules such D$_2$O, vertical-transition treatment not sufficient reproduce features seen experimentally double-ionization data.