Abstract
We visualize and control molecular dynamics taking place on intermediately populated states during different sequential double ionization pathways of CO2 using a sequence of two delayed laser pulses which exhibit different peak intensities. Measured yields of CO2 (2+) and of fragment pairs CO(+)/O(+) as a function of delay between the two pulses are weakly modulated by various vibronic dynamics taking place in CO2 (+). By Fourier analysis of the modulations we identify the dynamics and show that they can be assigned to merely two double ionization pathways. We demonstrate that by reversing the sequence of the two pulses it becomes possible to control the pathway which is taken across CO2 (+) towards the final state in CO2 (2+). A comparison between the yields of CO2 (2+) and CO(+)/O(+) reveals that the modulating vibronic dynamics oscillate out-of-phase with each other, thus opening up opportunities for strong-field fragmentation control on extended time scales.
Highlights
When a molecule interacts with a strong laser field multiple ionization, i.e., the loss of two or more electrons, may take place.1 Depending on whether the electrons are removed from the outermost or from lower lying valence shells during this process, the molecular ion will be created in the ground or excited ionic states, respectively
In a multiple ionization process, the final molecular ionic state may be reached via different pathways along intermediately populated ionic potential energy surfaces
It was recently shown for triple ionization of ethylene with laser pulses of different durations that a small increase in the delay between the second and third ionization steps determines whether the trication dominantly fragments into two, respectively, three moieties
Summary
When a molecule interacts with a strong laser field multiple ionization, i.e., the loss of two or more electrons, may take place. Depending on whether the electrons are removed from the outermost or from lower lying valence shells during this process, the molecular ion will be created in the ground or excited ionic states, respectively. The further fate of the molecule and therewith the outcome of a molecular fragmentation reaction depend on the history of all electron removal processes and on the delay between successive ionization steps It was recently shown for triple ionization of ethylene with laser pulses of different durations that a small increase in the delay between the second and third ionization steps determines whether the trication dominantly fragments into two, respectively, three moieties.. It was recently shown for triple ionization of ethylene with laser pulses of different durations that a small increase in the delay between the second and third ionization steps determines whether the trication dominantly fragments into two, respectively, three moieties.5 This behaviour could be explained to be due to the further stretch of the C–H bonds in the dication during this additional time.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
