In his dissertation, Marimuthu investigates interstellar molecules which were once thought to be very unlikely to exist in space due to the extreme conditions of the interstellar medium (ISM). This understanding began to change in the early 20th century with the discovery of several molecular species in the ISM. A revelation that challenged prevailing views and led to the development of new theoretical models about the chemical processes that occur in space.
Using the intense, tunable infrared laser light from HFML-FELIX, Marimuthu used a combination of spectroscopic methods – which provide spectral fingerprints and are crucial in studying interstellar molecules – and a cryogenic ion trap setup, to study molecular ions. The cryogenic trap allowed him to simulate ISM conditions and perform gas-phase action spectroscopy on cold molecular ions at <10K ambient temperature.
