Quantum optimal control for the full ensemble of randomly oriented molecules having different field-free Hamiltonians

Kurosaki, Yuzuru; Ichihara, Akira ; Yokoyama, Keiichi  

We have presented the OCT formulation to calculate optimal fields that can control the full ensemble of randomly-oriented molecules having different field-free Hamiltonians. The theory is applied to the fifty-fifty mixture of randomly-oriented CsI and CsI isotopomers and an optimal field is sought to achieve isotope-selective vibrational excitations with high efficiency. Rotational motion is frozen and two total times 's of electric field duration, 460000 and 920000 au (11.1 and 22.2 ps), are chosen in the present calculation. As a result, the final yields for = 460000 and 920000 a.u. are calculated to be 0.706 and 0.815, respectively. The relatively high final yield obtained for = 920000 a.u. strongly suggests that a single laser pulse can control the full ensemble of randomly-oriented non-identical molecules. The result is quite encouraging in terms of the application to isotope-separation processes.