Description du sujet de thèse

This project focuses on the structure and spectroscopy of cage-like carbon clusters to which hydrogen atoms can attach, thereby stabilizing the cage. These species are suspected to be responsible for the diffuse interstellar bands (DIBs), a series of absorption lines in the visible to infrared spectral range that occur when starlight passes through interstellar gas clouds.
Despite intense efforts since the discovery of the DIBs by Annie Jump Cannon (1919) and Mary Lea Heger (1922), most of these bands remain unidentified, although it is generally accepted that they are caused by carbon-based molecules. A major breakthrough was recently achieved with the discovery that several of these bands are due to C60+ (the cation of Buckminsterfullerene).
You will take part in the operation of a unique new instrument designed to generate and spectroscopically probe charged hydrogenated cages, in an effort to determine whether they are responsible for some of the unassigned DIBs.
The charged hydrogenated cages will be produced using a laser ablation source. They are then selected based on their shape and mass, trapped in a cryogenically cooled ion trap, and finally exposed to a tunable-wavelength laser beam to obtain electronic spectra that can be compared to astronomical observations.

Contexte de travail

ISMO is located in a new building on the Saclay plateau. The PhD student will benefit from ISMO's facilities as well as support from the laboratory's technical departments (mechanical workshop, instrumentation, electronics, and computing services). All components of the experimental setup at the heart of the PhD work have already been funded.