Doctoral defence: Mati Kook „Photoexcited processes in ionic liquid vapors“

On 22 January 2026 at 14, Mati Kook will defend his doctoral thesis "Photoexcited processes in ionic liquid vapors".

Supervisors:

Prof. Vambola Kisand, Institute of Physics, University of Tartu

Dr. Rainer Pärna, Institute of Physics, University of Tartu

Prof. Ergo Nõmmiste, Institute of Physics, University of Tartu

Opponent: Dr. Oksana Travnikova, Sorbonne Université, Laboratoire de Chimie Physique-Matière et Rayonnement, Paris, France

Summary

This thesis explores the electronic structure of selected ionic liquids (ILs) in the vapor phase, focusing on how different anion–cation combinations influence their electronic structure. The ILs were vaporized in high vacuum using an effusion cell. Ultraviolet photoelectron spectroscopy (UPS) and time-of-flight mass spectrometry (TOF-MS) measurements were performed at the new FinEstBeAMS beamline at the MAX IV Laboratory, where the author contributed to the construction and optimization (Paper I).

During the studies of ILs, the first UPS and in some cases TOF-MS spectra of the vapors of more than 10 ionic liquids: [EMIM][OTf], [PYR₁₄][OTf], [EMIM][DCA], [PYR₁₄][DCA], [PYR₁₄][TCM], [PYR₁₄][FSI], [PYR14][PF₆], [S₂₂₂][TFSI], [P₄₄₄₁][TFSI] and [EMMIM][TFSI] were obtained and published (Paper III-IV). The TOF-MS study on the fragmentation of [EMMIM][TFSI], [EMIM][OTf] and [EMIM][DCA] revealed the presence of interesting hydrogenated and dehydrogenated fragments (Paper II). The electronic structure of [EMIM][DCA] was thoroughly investigated (Paper IV-V). It was shown that [EMMIM][TFSI] and [EMIM][OTf] have similarities in the fragmentation pattern.