Bond rearrangement caused by sudden single and multiple ionization of water molecules

Strong-field-induced bond rearrangement in triatomic molecules

“…where M stands for the measured counts in each channel after subtracting false coincidences (described below), (1) P denotes all channels with a final dicationic charge state where only single dication products were measured, (including channels such as ABC 2+ , AB 2+ + C and A 2+ + BC), (2) P stands for all the two-body ion pair breakup channels (i.e., AB + + C + , B + + AC + , and C + + AB + ) and (3) P stands for all the three-body fragmentation channels where only the ion pairs are measured in coincidence (like A + + B + + C, A + + B + C + and A + B + + C + ). Note that the (1) P channels are multiplied by the detection efficiency, ε, to correct for the difference in detection efficiency of single ions (ε) with respect to ion pairs (ε 2 ), where we assumed the same detection efficiency for all ions.…”

“…The goal of the data analysis is the extraction of the yields of the various (1) P , (2) P and (3) P channels that are needed to calculate R. There are some complications to be addressed in this process: One factor is that due to non-uniform detection efficiency across the surface of the detector, we correct the yield for position dependent losses on our detector using known symmetries about the laser polarization. Additional complicating factors we address are the presence of false coincidences, which affect the yields of (2) P and (3) P , and the detection efficiency, which is needed to properly scale the (1) P yields and to subtract the contributions of higher charge states which affect the (3) P yield. The following paragraphs summarize how we address these points.…”

“…Since we are operating in the regime of ∼1 ion per laser pulse, we have a significant contribution from false coincidences, that is, coincident ions that arise from the fragmentation of two or more molecules in the same laser pulse. To reduce their effect on the the calculated branching ratio, we generate the false coincident ion pairs by randomly pairing ions from different laser pulses [2,[59][60][61]. Since we can generate an arbitrary number of random ion-pairs, we identify a purely random feature in any spectrum and generate enough false coincidences to match it, so it is properly subtracted.…”

“…Despite the increasing attention devoted to these processes, so far most studies have focused on a single molecular species and have occurred under an assortment of experimental conditions. For example, the initiating ioniza-tion mechanism in previous bond rearrangement studies has variously included single [8,11,[37][38][39][40][41][42] and multiple photons [5,22,26,27,43] as well as electron [23,28,44] and heavy ion impact [2,7,30]. To assist in understanding these dynamics we examine bond rearrangement following ultrafast strong-field double ionization of three triatomic molecules: carbon dioxide, carbonyl sulfide and water.…”

Nonadiabatic fragmentation of H2O+ and isotopomers. Wave packet propagation using ab initio wavefunctions

“…Our theoretical fragmentation branching ratios of D 2 O + compare satisfactorily with the experimental results of Eland, 11 and they support the small differences found between H 2 O + and D 2 O + species in photoelectron-photoion-coincidence experiments. 13,14 With respect to HDO + , time of flight coincidence experiments 23,24 in collisions of H + and F 7+ with HDO have shown a strong preference for breaking the O-H bond after both single and double ionization of the molecular species. In those experiments, it was also found that the isotopic effect is independent of the projectile, suggesting a kinematic effect at play in the post-collisional breakdown of HDO + and HDO 2+ .…”