Non-ergodic fragmentation of protonated reserpine using femtosecond laser activation

Specific fragmentation patterns are fingerprints that allow for unambiguous identification of molecules, for instance in analytical methods. To reveal and possibly control such specific fragmentation, it is essential to understand the physical processes involved during the activation step. We have performed on-the-fly (without trapping device) femtosecond (fs) laser activation/mass spectrometry experiments on gas phase protonated reserpine, a model molecular ion for analytical purpose, at different wavelengths and laser pulse intensities. In contrast to collision induced dissociation (CID) or 267 nm fs-laser activation, evidence of non-statistical fragmentation is observed when using 800 nm fs-laser activation. The associated mechanisms are discussed in terms of fragmentation induced by Coulomb repulsion after ultrafast ionization of the protonated molecule. Our results illustrate that the present on-the-fly experimental scheme can help in the understanding of the physics behind fs-laser activation. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Laser activation experiments were conducted on gas phase protonated reserpine at different wavelengths and laser pulse intensities, revealing evidence of non-statistical fragmentation with 800 nm femtosecond laser activation. Mechanisms of fragmentation induced by Coulomb repulsion after ultrafast ionization of the protonated molecule were discussed. This experimental scheme helps in understanding the physics behind femtosecond laser activation.