Dear Colleague,
Please call this announcement to the attention of any candidates who
might be interested.
Sincerely yours
Vincent
Postdoc : Energy transfer in nonlinear quantum lattices : application to
the vibrational energy flow in alpha-helices
Location: UTINAM Institute UMR-CNRS 6213
Université de Franche-Comté
25030 Besançon, cedex, FRANCE
Length: 9 months, starting as soon as possible considering the time
needed by the person retained to get all the administrative papers
necessary to work in France.
Financial conditions: The credits obtained allow us to warrant a gross
salary of 1839 € per month, which in reality means 1508 € per month
transferred on the bank account.
Requested profile: To develop these researches, we are looking for a
candidate who has a strong background in either quantum non-linear
dynamics, non equilibrium statistical mechanics, transport properties,
dissipation, energy localization in molecular system or numerical
analysis (i.e. ab initio calculations) applied to condensed or soft
matter. In any case, the person retained must have completed his/her PHD
since less than 2 years and NOT be of French nationality! Therefore, the
applicants should enclose in their application, considerations allowing
assessing the time they would need to get the authorization to work in
France.
Contact : The applicants should send a detailed CV and a publications
list to Dr. POUTHIER Vincent at :
[log in to unmask]
Summary of the project:
Since the seminal work of Davydov on bioenergy transport in proteins,
both theoretical and experimental evidences suggest that vibrational
energy flow in alpha-helices may result from a polaron mechanism. The
energy is mediated by the amide-I vibration which delocalizes along the
peptide leading to the formation of an exciton called vibron. The vibron
strongly interacts with the phonons describing the collective dynamics
of the H-bond network. Therefore, its creation induces a lattice
distortion and the vibron dressed by this distortion forms the so-called
small polaron.
In that context, the project concerns the study of the transport
properties of polaron or bi-polaron in a lattice of H bonded peptide
units by taking into account on the very short lifetime of the amide-I
vibration. Indeed, most of the previous works were based on Hamiltonians
that conserve the polaron population. However, in proteins, the amide-I
energy relaxation is rather fast and recent experiments have clearly
shown that the polaron lifetime is typically of about T1=1.5 ps. The
relaxation originates from intramolecular energy redistribution due to
the anharmonic coupling between each amide-I mode and a set of
intramolecular normal modes whose displacements are strongly localized
on the C=O groups. Therefore, the Complex Structure Dynamics group of
the UTINAM Institute is looking for a candidate able to develop one of
the two following topics :
- Developing analytical models/calculations to study the transport
properties in a finite site helix within a time convolutionless approach
to account on the strong non markovian dynamics that arises from the
discrete nature of the phonon energy spectrum.
- Performing ab initio calculations to characterize the detailed
relaxation pathways responsible for the energy relaxation of the amide-I
mode in a model helix. These calculations will give rise to a
theoretical model to represent the bath of intramolecular normal modes
responsible for energy relaxation.
--
Dr. POUTHIER Vincent
Chargé de Recherche CNRS
Institut UTINAM UMR CNRS 6213
25030 BESANCON cedex
tel. 33 3 81 66 64 77
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