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arXiv · 0812.2135

Strong fields induce ultrafast rearrangement of H-atoms in H$_2$O

F. A. Rajgara·D. Mathur·A. K. Dharmadhikari·C. P. Safvan
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Abstract

H-atoms in H$_2$O are rearranged by strong optical fields generated by intense, 10 fs laser pulses to form H$_2^+$, 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 $\sim$300-attosecond long strong fields generated using fast Si$^{8+}$ ions helps establish thresholds for field strength and time required for such rearrangements. Quantum-chemical calculations reveal that H$_2^+$ originates in the $^1$A state of H$_2$O$^{2+}$ when the O-H bond elongates to 1.15 a.u. and the H-O-H angle becomes 120$^o$. Bond formation on the ultrafast timescale of molecular vibrations (10 fs for H$_2^+$) has hitherto not been reported.

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F. A. Rajgara, D. Mathur, A. K. Dharmadhikari, C. P. Safvan. 2008-12-11. Strong fields induce ultrafast rearrangement of H-atoms in H$_2$O. https://doi.org/10.1063/1.3157234

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