[CP2K-user] Post-doc in Toulouse, France
Merlin Meheut
merlin... at gmail.com
Tue Feb 2 08:49:50 UTC 2021
Dear all,
I have a new two years postdoctoral position in my group.
Please see below for further information and links
Best Regards,
Title: Molecular simulations to predict the fractionation of isotopes in
the environment (GET)
Applications are invited for a Postdoctoral Research Associate at Toulouse
University (GET laboratory), working with Dr Merlin Méheut (
https://www.get.omp.eu/author/merlin-meheut/ ) and Dr Magali Benoît (CEMES,
Toulouse), in the framework of an ANR “Young Researcher” project. We are
looking for talented and highly motivated candidates to realize molecular
dynamics calculations (both empirical and ab initio) for Environmental
Sciences. The Associate will collaborate with experimental scientists at
GET (Coll G Saldi, J Schott) and LHyGeS, Strasbourg (Coll A.D Schmitt), and
with chemical theoricists at ENS, Paris (coll R. Vuilleumier), NYU (M.
Tuckerman) and CMC, Strasbourg (R. Schurhammer). Candidates motivated by
multidisciplinary research and application of atomistic simulation to
complex natural systems will be appreciated.
To apply for this position, please connect to the following link :
https://bit.ly/3oo5NyI
*Scientific context*
Isotopic compositions of natural phases constitute a tool of primary
importance to assess geological history. Recent progresses in mass
spectrometry and analytical chemistry have enabled the detection of
isotopic variations of a host of elements (e.g. Fe, Mg, Ca, Li, Zn),
opening the path to numerous applications. In particular, Ca isotopes have
shown their potential for medical applications (early diagnosis of
decalcification), to assess mechanisms occuring at the soil-plant
interface, or to assess the Ca cycle in the environment.
To take the full extent of these new measurements, it is necessary to
precisely constrain the isotopic effect associated with elementary
processes occuring at the atomic level. In this perspective, the
fractionation of isotopes reached at thermodynamical equilibrium (called
equilibrium fractionation) between two phases (between one mineral and a
dissolved species, or between two dissolved species) is of particular
interest.
It is possible to estimate isotopic fractionation based on atomistic
modeling by estimating the thermo-kinetic properties of atoms in a given
bonding environment. For solids, these properties are generally estimated
based on the harmonic approximation, starting from the vibrational
frequencies of the mineral (e.g. Méheut and Schauble 2014). For liquids, we
have developed an approach based on path integral molecular dynamics (PIMD,
Dupuis et al 2017). This approach, which was applied to Li isotopes, is
computationally very expensive, and that is why it has been limited so far
to the use of empirical potentials to describe atomic interactions.
Our primary goal is to set an affordable numerical scheme to compute
equilibrium fractionation properties of any material, in particular
dissolved species, based on path integral molecular dynamics methods, but
with atomic bonding described by ab initio electronic structure
computations (instead of empirical potentials), so as to render its
application to virtually any case. This approach will be first tested on
the Ca²⁺-H2O system for which experimental data exist.
*Description of the position:*
The work of the researcher will be to set up path integral molecular
dynamics on a Ca2+-H2O system, with empirical potentials (with the CP2K
code), in order to compute Ca isotopes fractionation properties for this
system. This will be first realized with empirical potentials, then with an
ab initio approach. Depending on the avancement, another task of the
postdoc may be to realize some calculations on solids, based on the
well-controlled approach based on the harmonic approximation.
To apply for this position, please connect to the following link :
https://bit.ly/3oo5NyI
CV and motivation letter will be requested.
*Required technical skills:*
- Use of ab initio molecular dynamics codes: CP2K, CPMD, CP, PINY-MD. Good
level.
- Possibly expertise to build empirical potentials by inverse Monte Carlo
approach.
- Possibly experience in path integral molecular dynamics.
*Knowledge to put in application:*
- Operating molecular dynamics algorithms
- Path integral formulation of quantum mechanics.
*Know-how :*
- Computer programming : good level
- Developing a scientific approach to set up a methodology aiming at
reproducing a quantity measured experimentally.
- Estimating the different sources of error and their consequences on the
final result.
*Some papers in relation to the proposed work:*:
Dupuis R., Benoît M, Tuckerman M, Méheut M. (2017), Accounts of chemical
research 50 (7), 1597-1605
Méheut M. and Schauble E.S. (2014), Geochimica et Cosmochimica Acta 134,
137-154
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