Offer 39 out of 62 from 04/06/24, 16:31


Freie Universität Berlin - Institut für Geologische Wissenschaften - Arbeitsbereich Mineralogie-Petrologie

Research assistant (Postdoc) (m/f/d)

full-time job
limited to 31.12.2026
salary grade (Entgeltgruppe) 13 TV-L FU
reference code: Min-Pet/05/2024

Working field:

The position is located in the Mineralogy-Petrology group (Prof. Dr. John) at the Institute of Geological Sciences, whose research focuses on fluid-rock/solid interaction, the thermodynamics of fluids and rocks, reactive fluid flow and its chemical and petrophysical consequences, and time scales of metamorphic and metasomatic processes. The research group offers an intercultural, open-minded, versatile and family-friendly working environment.

Job description:
The project will investigate the interactions between high field strength elements (HFSE) and fluoride in geological fluids. The focus will lie on synchrotron experiments but other experimental methods or field-based studies can be included, depending on the expertise and inclinations of the postdoctoral researcher. The position is related to the Collaborative Research Center (CRC) 1349 "Fluorine-Specific Interactions", where 50 PhD students and PostDocs are conducting research in the field of fluorine chemistry in 20 working groups of the Freien Universität Berlin, the Humboldt University Berlin, the Technical University Berlin, the Federal Institute for Materials Research and Testing and the Leibniz Research Institute for Molecular Pharmacology on fluorochemical issues.

Planned parts:

  1. Valence to Core X-ray emission spectroscopy (VtC XES) of the L3 edge of Hf in solid materials.
  2. Expansion of the VtC method to aqueous systems at up to 400°C and 400 bar to investigate ligand identities of various HFSE complexes. The main focus will be on fluoride complexes of Zr, Hf, Nb, and Ta in fluoride-rich solutions.
  3. Investigation of HFSE complexation in silicate-rich aqueous solutions with similar methods. This part may involve autoclave or hydrothermal diamond anvil cell experiments and may also use Raman spectroscopy.
  4. Characterization of complexation behavior of rare-earth elements under geologically relevant conditions with Raman spectroscopy. We have already measured about half of the lanthanoid fluorides at BESSY in Berlin. The remaining lanthanoid fluorides will need to be measured and analyzed in collaboration and coordination with Colleagues from the CRC.
    Further developments will depend on the outcomes of the parts outlined above. The successful applicant will have the opportunity to modify or add to the research plan according to their own interests in coordination with the wider team.


A successfully completed university degree (M.Sc. or diploma) in geology, mineralogy or chemistry and a successfully completed doctorate in geology, mineralogy, chemistry or a research field relevant to the area of responsibility with a predominantly geological focus.


  • Experience in laboratory and analytical work is required
  • Responsible and mindful handling of hazardous chemicals, including concentrated hydrofluoric acid, is a prerequisite
  • background in synchrotron-based spectroscopic research, X-ray spectrography, or fluid chemistry processes and willingness to learn more of it
  • Experience with high-p-T experimentation is useful
  • The project involves coordinating teams of researchers from diverse fields, therefore, fluency in English is very important
  • Fluency in German is a plus

How to apply:

For further information, please contact Mr. Prof. Dr. Timm John ( /
+49 (0)30-838-70103).

Applications should be sent by e-mail, together with significant documents, indicating the reference code, no later than July 1st, 2024 in PDF format (preferably as one document) to Mr. Prof. Dr. Timm John: or postal to

Freie Universität Berlin
Fachbereich Geowissenschaften Institut für Geologische Wissenschaften Arbeitsbereich Mineralogie-Petrologie Herrn Prof. Dr. Timm John
Malteserstr. 74-100
12249 Berlin (Lankwitz)

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Freie Universität Berlin is an equal opportunity employer.