Atom probe tomography is an established method for the microsocopic analysis of hard materials, which stands out by combining single-atom sensitivity with a 3D volume reconstruction. The method is based on laser-assisted field evaporation from nanometric emitter tips. In solid state reactions it delivered decisive information to understand the detailed conditions of nucleation and growth of product phases. In recent efforts, we desire to break the materials limitations aiming for application to liquids, softmatter and polymeric materials. To this end, a new instrument has been constructed that joins cryogenic ion beam preparation with a flexible transfer into an atom probe chamber. Meanwhile, we are able to produce nanometric needles from frozen liquids, even from pure water [1]. Studies are performed with aqueous solutions [2], liquids of short alkanes [3], self-assembling monolayers [4]. The talk discusses the field desorption of complex materials and presents time of flight mass spectra and their dependence on field or laser intensity. The complex mechanisms of field desorption from frozen water surfaces are further elucidated by DFT and Monte-Carlo simulation. Finally, by evaluating evaporation probabilities and event correlations, even insight in bonding strength and the stability of molecules in strong electrical fields may be provided.[1] T. M. Schwarz, E. M. Weikum, K. Meng, E. Hadjixenophontos, C. A. Dietrich, J. Kästner, P. Stender, G. Schmitz, Field evaporation and atom probe tomography of pure water tips, Nature Scientific Reports (2020) 10:20271 | (DOI: 10.1038/s41598-020-77130-x[2] T. M. Schwarz, C. A. Dietrich, J. Ott, E. M. Weikum, R. Lawitzki, H. Solodenko, E. Hadjixenophontos, B. Gault, J. Kästner, G. Schmitz, P. Stender, 3D Sub-Nanometer Analysis of Glucose in an Aqueous Solution by Cryo-Atom Probe Tomography, Scientific reports 11 (2021) 11607 (DOI: 10.1038/s41598-021-90862-8)[3] Kuan Meng, Tim Schwarz, Eric Weikum, Patrick Stender, Guido Schmitz, Frozen n-Tetradecane investigated by cryo-Atom Probe Tomography, J. Microsc. Microanal. (2021), 1-11; (DOI:10.1017/S14319276210125)[4] Helena Solodenko, Patrick Stender, Guido Schmitz, “Atom Probe Study of 1-octadecanethiol self-assembled Monolayers on Platinum (111) and (200) surfaces”, J. Microsc. Microanal. (2021), 1–10. (DOI: 10.1017/S1431927621012654)
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