Charge Resonance Enhanced Ionization (CREI) of Molecules in Intense Laser Fields Available to Purchase

Short (τ≤100 fs) intense $(I≥ 1014 W/cm2)$ laser pulses are shown from nonperturbative numerical simulations of the time‐dependent Schroedinger equation to induce unusually large ionization rates in molecules often exceeding those of the dissociated fragments. Linear one electron, $H2+,$ $H3++$ and two electron systems $H2,$ $H3+$ have been studied numerically in order to understand this phenomenon. It will be shown that enhanced ionization is due to the existence of large divergent transition moments in these symmetric molecules due to degeneracies of electronic orbitals upon dissociation. Such degenerate states called charge resonance states in 1939 by Mulliken, give rise to charge resonance oscillations. We show that these charge resonance states are responsible for charge resonance enhanced ionization, CREI. A static field picture of CREI will be shown to explain adequately the enhanced ionization and the critical distances at which it occurs through field induced barrier suppression of the electron‐nuclear coulomb potentials in these molecular systems.