Double Photodetachment of F^–·H₂O: Experimental and Theoretical Studies of [F·H₂O]⁺

Abstract

Double photodetachment of the cluster F − •H 2 O in a strong laser field is explored in a combined experimental−theoretical study. Products are observed experimentally by coincidence photofragment imaging following double ionization by intense laser pulses. Theoretically, equation of motion coupled cluster calculations (EOM-CC), suitable for modeling strong correlation effects in the electronic wave function, shed light on the Franck−Condon region, and ab initio molecular dynamics simulations also performed using EOM-CC methods reveal the fragmentation dynamics in time on the lowest-lying singlet and triplet states of [F•H 2 O] + . The simulations show the formation of H 2 O + + F, which is the predominant experimentally observed product channel. Suggestions are proposed for the formation mechanisms of the minor products, for example, the very interesting H 2 F + , which involves significant geometrical rearrangement. Analysis of the results suggests interesting future directions for the exploration of photodetachment of anionic clusters in an intense laser field.

Simultaneous electrostatic trapping of merged cation & anion beams

“…In the experiments described here, a mixture of B200 PSI argon carrier gas, seeded by B5% of SF 6 sample gas was expanded into the source chamber and ionized by a pulsed circular electron gun that directs B200 eV electrons into the supersonically expanding gas, generating a variety of cation and anion species. [65][66][67][68][69] The supersonic expansion is skimmed by an 8 mm skimmer located 100 mm downstream of the pulsed valve. Such setup enables trapping very heavy molecules without analyzing magnet mass limit.…”