Strong fields induce ultrafast rearrangement of H-atoms in H2O
Abstract
H-atoms in H2O are rearranged by strong optical fields generated by intense, 10 fs laser pulses to form H2+, against prevailing wisdom that strong fields inevitably lead to multiple molecular ionization and the subsequent Coulomb explosion into fragments. This atomic rearrangement is shown to occur within a single 10 fs pulse. Comparison with results obtained with 300-attosecond long strong fields generated using fast Si8+ ions helps establish thresholds for field strength and time required for such rearrangements. Quantum-chemical calculations reveal that H2+ originates in the 1A state of H2O2+ when the O-H bond elongates to 1.15 a.u. and the H-O-H angle becomes 120o. Bond formation on the ultrafast timescale of molecular vibrations (10 fs for H2+) has hitherto not been reported.