Ultrafast formation dynamics of D3+ from the light-driven bimolecular reaction of the D2-D2 dimer

The light-driven formation of trihydrogen cation has been attracting considerable attention because of its important role as an initiator of chemical reactions in interstellar clouds. To understand the formation dynamics, most previous studies focused on creating H-3(+) or D-3(+) from unimolecular reactions of various organic molecules. Here we observe and characterize the ultrafast formation dynamics of D-3(+) from a bimolecular reaction, using pump-probe experiments that employ ultrashort laser pulses to probe its formation from a D-2-D-2 dimer. Our molecular dynamics simulations provide an intuitive representation of the reaction dynamics, which agree well with the experimental observation. We also show that the emission direction of D-3(+) can be controlled using a tailored two-colour femtosecond laser field. The underlying control mechanism is in line with what is known from the light control of electron localization in the bond breaking of single molecules.

Automated summary

The formation of trihydrogen cation driven by light has been of great interest due to its important role in initiating chemical reactions in interstellar clouds. Previous studies focused on the formation of H-3(+) or D-3(+) from unimolecular reactions, but we observed and characterized the ultrafast formation of D-3(+) from a bimolecular reaction. Molecular dynamics simulations provided an intuitive representation of the reaction dynamics, which matched well with experimental observations. Additionally, we demonstrated control over the emission direction of D-3(+) using a tailored two-colour femtosecond laser field, based on the mechanism known for light control of electron localization in single molecules.