Prolongation of electronic coherence for ultralong-lived charge migration anchored by a continuous-wave laser

In ideal scenarios, charge migration (CM) moves electronic charge coherently from one molecular end to the other, with periods from several hundred attoseconds to a few femtoseconds. Here we show that a well-designed continuous-wave laser can prolongate electronic coherence by more than two orders of magnitude. This enables ultralong-lived CM. The effect is demonstrated by quantum dynamics simulations for the example of ${\mathrm{HCCI}}^{+}$ prepared in a superposition of the electronic ground and first excited states. The success is due to straightforward control of the three laser parameters, i.e., the field strength, the frequency, and the carrier envelope phase, to anchor the nuclei close to the Franck-Condon point, with equal populations of the two electronic states.