Rapid Proton Transfer Mediated by a Strong Laser Field

Kinetic energy distributions of ${\mathrm{H}}^{+}$ ejected from a polyatomic molecule, anthraquinone, subjected to 60 fs, 800 nm laser pulses of intensity between 0.2 and $4.0\times {10}^{14}\mathrm{W}·{\mathrm{cm}}^{-2}$, reveal field-driven restructuring of the molecule prior to Coulomb explosion. Calculations demonstrate fast intramolecular proton migration into a field-dressed metastable potential energy minimum. The proton migration occurs in the direction perpendicular to the polarization of the laser field. Rapid field-mediated isomerization is an important new phenomenon in coupling of polyatomic molecules with intense lasers.