First-principles modelling of vibrational hot bands of spherical

Proposition de stage
Année universitaire 2016-2017
Fin d’études MASTER 2 Recherche ou Ecole d'ingénieur
Laboratory
Commissariat à l’énergie atomique et aux énergies alternatives
Service de Corrosion et du Comportement des Matériaux dans leur Environnement
SCCME - CEN/Saclay - 91191 Gif sur Yvette Cedex
Tutor
Philippe ZELLER - Tél : (+33) (0)1 69 08 80 89 - [email protected]
Duration
from 4 to 6 months, beginning between January and March 2016
Salary
- Monthly allowance depending on previous diplomas.
- Final bonus depending on achievements.
- Partial housing allowance (conditional).
First-principles modelling of vibrational hot bands
of spherical-top molecules
Context
SF6, CF4, CH4 are powerful greenhouse gases contributing to global
warming. Measurement of their atmospheric concentration requires an
a priori knowledge of their theoretical infrared absorption spectrum
with a high precision. The relevant molecular constants which are
stored in large international databanks are however currently
insufficient to describe the vibrational hot bands of these threee
molecules. Determination of these constants based on experimental spectra, using state-of-the-art
techniques, are hindered by the huge complexity of these spectra.
Aim and approach
The goal is to determine missing constants using ab initio atomistic modelling. For each molecule
the approach is made up of three main steps : building a potential energy surface using electronic
structure calculations within either quantum chemistry or density-functional theory, solving the
Schrödinger equation for the nuclei in the Born-Oppenheimer approximation, which will output the
frequencies of band origins, and inclusion of these constants in the general procedure for spectrum
analysis using the HTDS and STDS codes. The large number of constituent atoms of these
molecules and their high symmetry are two original features of the problem which will make it
necessary to design a specific methodology and an informed choice of complementary
approximations.
The internship will aim at proposing a detailed methodology and finding arguments to support it in
the literature and in preliminary calculations assessing the feasibility. It may be extended by a
3-year project towards a Ph.D degree which will be supervised by V. Boudon (ICB, Dijon).
Collaboration
Vincent BOUDON, DR CNRS. Laboratoire ICB, Univ. de Bourgogne Franche-Comté, Dijon
Relevant techniques
Atomistic modelling - First-principles electronic structure calculations - High Performance
Scientific Computing - HTDS et STDS molecular spectroscopy codes
Pre-requisites
Quantum physics - Quantum chemistry - Molecular physics - Applied mathematics