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C.P.M.O.H. (UMR5798)
Université Bordeaux 1
351 Cours de la Libération
33405 TALENCE Cedex
Tél.: +33 (0)5 4000 2890
Fax : +33 (0)5 4000 6970

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Postdocs > Post-Doc Opportunity > Calculation of optical spectra of large molecules from TDDFT linear response, using a new algorithm

Postdoctoral position in theoretical physical chemistry / applied mathematics:

Calculation of optical spectra of large molecules from TDDFT linear response, using a new algorithm

Contact : FOERSTER Dietrich - (15 October 2007)

Host Universities: University of Bordeaux 1, University of Pau, France

Host laboratories: Centre de Physique Moléculaire Optique et Hertzienne (CPMOH-UMR5798 CNRS and UB1) and

 Institut pluridisciplinaire de recherche sur l’environnement et les matériaux (IPREM-UMR5254 CNRS and UPPA)

Collaborators: D. Foerster (CPMOH), I. Baraille (IPREM, Pau)

Starting: January 2008

Duration: 1 year, renewable twice

Net salary ca. 2100 euros

 

Research project:

 

This postdoctoral position is to finalize deployment of a novel O(N3) TDDFT code for the calculation of molecular optical spectra using the linear response equations of Gross, Petersilka, Gossmann (1) rather than Casida’s equations (2) that are used and implemented in most available DFT codes. Part of our motivation is that these equations are more convenient for systems with boundary conditions, such as molecules adsorbed on surfaces.

A new algorithm developed by D. Foerster eliminates the need of a severe approximation made in an earlier attempt to solve these equations by Blase and Ordejon (3) while avoiding combinatorial explosion by a mathematical technique that is new in this context (4). Acceleration compared to existing O(N3) codes will be explored in calculations starting with the reference compound benzene and continuing with progressively larger molecules such as cyano-anthracenes and dyes like indigo and naphthol yellow, comparing throughout with experimental data and checking scaling with system size.

The candidate will participate in the last stages of code development and optimization which may involve recoding J.Talman’s fast Hankel transform (5) that plays an essential role in this project. The code will be interfaced with the SIESTA package, implying optimisation and parallel programming. These tasks will be carried out in contact with, respectively, one of the originators of the siesta code (D. Sanchez-Portal at DIPC San Sebastian, Spain) and with computer scientists and applied mathematicians at Bordeaux (O. Coulaud) while making use of the 256 parallel processors that are available at the local computer center.

Because of the rather general caracter of the concepts and mathematical techniques to be used, experience gained by the candidate in the context of this project should be transposable to, and useful in, other fields of computational materials science.

 

Context: This position is part of an ANR-funded project in south-west France: NOSSI, ’Nouveaux outils pour la simulation des solides et interfaces’ (’New tools for the simulation of solids and interfaces’).

 

Previous experience of the candidate:

Candidates should have a strong background in scientific programming and, if not actually expert, at least interested in density functional theory. Experience with parallel programming is not necessary, but would be greatly appreciated.

This postdoctoral position may also interest applied mathematicians, because it concerns the implementation of a new calculational algorithm.

 

Scientific environment:

The university of Bordeaux is recognized for its excellence in several fields relevant to this project: optical spectroscopy, molecular and solid state chemistry and meso- and nanostuctured materials. In the domain of applied mathematics, it is renowned for its development of computational algorithms. The university of Pau has proven expertise in the fields of materials and surface characterization and solid state quantum chemistry. The position offers opportunities for cross-disciplinary research in a well-equipped and pleasant working environment. Candidates will be expected to interact closely with colleagues providing experimental data for the validation of the calculations. Travel between the participating centres (Bordeaux, Pau, San Sebastian) will be required.
 

Contacts:

D. Foerster, d.foerster@cpmoh.u-bordeaux1.fr, Tel: +33 (0) 54000 2507

I. Baraille, isabelle.baraille@univ-pau.fr, Tel : +33 (0) 55940 7845
 

References:

1 M. Petersilka, U. J. Gossmann, and E. K. Gross, Phys. Rev. Lett. 76, 1212 (1996).
2 M.E. Casida, in Recent Advances in Density Functional Methods, Part I, edited by D.P. Chong (Singapore, World Scientific, 1995), p. 155;
3 X. Blase and P. Ordejon Phys. Rev. B 69 (2004) 085111.
4 D. Foerster, to be published in Journal of Chemical Physics.
5 J. Talman, J. Comp. Phys. 29, (1978) 35; Comput. Phys. Comm. 30 (1983), 93.

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