Strong-field-induced bond rearrangement in triatomic molecules

Abstract

A comparative study of bond rearrangement is reported for the double ionization of three triatomic molecules: carbon dioxide, carbonyl sulfide, and water (D2O). Specifically we study the formation of the molecular cation AC + from the edge atoms of a triatomic molecular dication ABC 2+ following double ionization by intense, short (23 fs, 790 nm) laser pulses. The comparison is made using the double ionization branching ratio of each molecule, thereby minimizing differences due to differing ionization rates. The rearrangement branching ratio is highest for water, which has a bent initial geometry, while CO2 and OCS are linear molecules. The angular distribution of O + 2 fragments arising from CO2 is essentially isotropic, while SO + from OCS and D + 2 from D2O are aligned with the laser polarization. In the CO2 and D2O cases, the angular distributions of the bond rearrangement channels are different from the angular distributions of the dominant dissociative double ionization channels CO + + O + and OD + + D + . Only the angular distribution of SO + from OCS is both aligned with the laser polarization and similar to the angular distribution of the largest dissociative channel, CO + + S + . The mixed behavior observed from the angular distributions of the different molecules stands in contrast to the relative consistency of the magnitude of the bond rearrangement branching ratio.I.

Controlling H3+ Formation From Ethane Using Shaped Ultrafast Laser Pulses

“…The experimental techniques applied in this study have recently been discussed elsewhere [21,36], and in this section we will only highlight a few key points. Two different approaches are used to examine the interactions of intense laser pulses with ethane gas: First, the laser pulses are shaped using an acousto-optic programmable dispersive filter (AOPDF) [37] and the ethane reaction products are measured using velocity map imaging (VMI) [38,39].…”

“…Following the procedure outlined in Ref. 36 for removing false coincidences, we use this data to obtain the two-body doubleionization branching ratio reported in Table 1.…”

“…Since the control experiments with the D 3 C-CH 3 isotopologue of ethane are designed to distinguish between the involvement of the hydrogen atoms on one or both sides of the molecule, the angular distributions from the VMI data might provide information about the dissociation dynamics beyond the KER shift shown in Figure 2B. Since the angular COLTRIMS data can be readily corrected using available experimental symmetries [36], we compared the COLTRIMS-measured D + 3 + C 2 D + 3 angular distribution to the weighted sum of the D 2 H + and D + 3 VMI angular distributions to derive a function that ensured uniform detection efficiency across the VMI detector.…”

Αλληλεπίδραση ισοτοπολόγων του νερού με fs ασύμμετρα ω/2ω πεδία laser

“…Αρχικά, το πιο πιθανό διασπαστικό κανάλι σε αυτές τις πειραματικές συνθήκες είναι το κανάλι (I), το οποίο οδηγεί σε θραύσματα 5.0 eV κινητικής ενέργειας (KER). Η παρατήρηση αυτή συμφωνεί με μελέτες της βιβλιογραφίας[ 104 ].…”

“…], του φωτοιονισμού από πηγές υπεριώδους[ 70 ], αλλά και ισχυρά πεδία laser [104,106,109,118 ].Στην περίπτωση των ισχυρών πεδίων, έχει παρατηρηθεί από τους Rajgara et al[ 118 ], χρησιμοποιώντας fs παλμούς laser λίγων οπτικών κύκλων στα 800 nm. Το κατώφλι έντασης που προσδιόρισε η συγκεκριμένη ερευνητική ομάδα, είναι περίπου 2.0 x 1015 W/cm 2 .…”