Bayi Glacier in Qilian Mountain, China (Credit: Xiaoming Wang, distributed via

Job advertisement 12-months postdoctoral scientist at GSMA

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European Geosciences Union

12-months postdoctoral scientist at GSMA

12-months postdoctoral scientist at GSMA

GSMA, UMR CNRS 7331 logo


The Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA) is a unit of CNRS (Centre National de la Recherche Scientifique) under the auspice of INP (Institut National de Physique) and INSU (Institut National des Sciences de l’Univers). The unit is localized on the UFR Sciences campus, 45-min by train from Paris. The GSMA is a unit specialized in spectroscopy and atmospheric physics.

Reims, France


Relevant division
Atmospheric Sciences (AS)




Preferred education

Application deadline
Open until the position is filled

3 December 2020

Job description

ICAR HO2 proposes to develop an innovative scientific instrument for an absolute, direct measurement of HO2 concentration in the atmosphere, as a first step toward an absolute and direct detection of OH radical (concentration 1-2 order of magnitude lower than HO2). The development of such instrument is expected to have tremendous scientific impact on the understanding of atmospheric chemistry and benefit from supports from Princeton University, NIST (National institute of Standards and technology, USA) and Jülich Forschungszentrum.

Radicals play a major role in the atmospheric chemistry, in particular OH and HO2 (hydroxyl and hydroperoxyl radicals) in the daytime. The OH radical is the major oxidant of all trace gases in the atmosphere. Its concentration is closely linked to the HO2 concentration via a rapid recycling of HO2 back into OH through reaction with NO or radical-radical reactions in remote environments. The measurement of their concentration is thus vital to identify a lack in the understanding of gas phase oxidation processes. Therefore, many efforts have been made in the last decades to develop sensitive instruments for a reliable quantification of both radicals, a difficult task due to their high reactivity and their subsequently low concentrations (ppt). However, these instruments are most of the time very costly, bulky and request calibration and chemical conversion (in particular for HO2, leading to interferences).

The successful applicant will join a collaborative project between GSMA, ULCO, PC2A and international partners as Princeton University, NIST and Jülich Forschungszentrum.
The project aims at developing an innovative instrument based on a combination of Balanced-Detection Faraday Rotation Spectroscopy (BD-FRS) with Frequency-Stabilized Cavity-Ring Down Spectroscopy (FS-CRDS) in order to further improve the LoD by benefitting from the unique advantages of FRS (noise suppression and interference-free with diamagnetic compounds (H2O, CO2 …) and CRDS (km long absorption approach). In this frame, the GSMA is involved in the development of a frequency-stabilized cavity ring-down spectrometer (FS-CRDS, location : GSMA, Reims, France) which will, in fine, be coupled to a Faraday Rotation system (FRS) at the Université du Littoral Côte d’Opale (ULCO, Dunkerque, France).

  • To develop the FS-CRDS together with the team at GSMA
  • Participate to the discussions about measurement strategies
  • Be involved in the tests and calibration of the instrument
  • Participate to calibration campaigns : LPCA CHARME chamber, in comparison with the UL-FAGE of PC2A & comparison with the FZJ-FAGE (Forschungscentrum of Jülich-FAGE) in the Simulation of Atmospheric PHotochemistry In a large Reaction Chamber (SAPHIR) at Forschungscentrum of Jülich.
  • Disseminate the results through high-quality peer-review publications and presentations at conferences

He/she is susceptible to extend his/her postdoc at ULCO for the hybridization of FS-CRDS with FRS (additional 18 months contract).


  • A PhD in physics, atmospheric sciences, chemistry with a strong background on atmospheric radicals and instrumental development.
  • Excellent programming skills (Labview, Matlab, …) and scientific tools (Origin,…)
  • Experience in Cavity Ring Down Spectroscopy
  • An ability to work independently and to effectively communicate their research to colleagues and the scientific community more broadly.
  • Strongly motivated and willingness to integrate the project team
  • Willingness to travel nationally and internationally

How to apply

Please, submit:

  • A curriculum vitae including a list of publications and research experience
  • The names and contact information of at least two referees
  • A concise letter of motivations (1 page max)

Deadline for applying
Applications received prior to June 1st, 2021 will receive full consideration, but the position will remain open until filled. The preferred start date is fall 2021, but may be negotiable, particularly in light of the evolving COVID-19 situation.

For further information, please contact Dr. Mélanie Ghysels-Dubois :