Laboratoire Francis PERRIN
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The GOUTTELIUM setup : an IR spectroscopy in a cold environment
Last Update: 29 July 2014

Etude du photorécepteur "Photoactive Yellow Protein" par dichroïsme circulaire femtoseconde
Last Update: 21 February 2016

L'interaction médicament-protéine étudié par spectroscopie de fluorescence résolue en temps
Last Update: 9 December 2013

"Cœur silicium - coquille carbone" pour batteries Li-Ion
Last Update: 6 October 2015

Dynamic of peptids in gas phase and photostability of proteins
Last Update: 21 May 2013

A method to observe the complete vibrational spectrum of ionized molecules
Last Update: 21 May 2013

The strength of the NHamide---Smethionine revealed by spectroscopy of small peptides
Last Update: 21 May 2013

Imagerie photochimique du champ proche optique de nanocubes d’or
Last Update: 15 March 2012

Des tapis de nanotubes alignés, en grande surface !
Last Update: 31 January 2012

Nouvelles lumières sur l’interaction entre les rayons UVA et l’ADN
Last Update: 3 February 2014

Synergy btetween experiment and theory for the simulation of protein folding
Last Update: 21 September 2010

Un nouveau composé aux propriétés intéressantes d'absorption optique dans le domaine visible : TiO
Last Update: 17 June 2010

Synthèse de nanotubes marqués au carbone 14 pour des études de biodistribution
Last Update: 13 January 2011

A surprising dynamic of cluster fragmentation
Last Update: 13 November 2007

Chirality and folding of peptide chains
Last Update: 23 March 2007

Recent results in physicochemistry with the very new laser PLFA
J.M. Mestdagh, L. Poisson, I. Fischer, P. D’Oliveira
Service des Photons, Atomes et Molécules DRECAM/SPAM

The very new laser of the "Plateforme Laser Femtoseconde Accordable, PLFA" began to be installed last year within the Service of Photons Atoms and Molecules (SPAM). It belongs to the infrastructure SLIC, member of the European network LASERLAB-EUROPE and is thus accessible to European scientists. It was designed according to several bets: high repetition rate (1 Khz), strong pulse energy (up to 13mJ, at 800nm), broad accordability (500-750nm) and ultra-fast pulses (<35 fs = 35 10-15 s).

The requirement of a wide wavelength range, even difficult to realize, is necessary to allow decisive progress in physico-chemistry of fast reactions. The requirements in pulse duration were chosen to probe efficiently the dynamics of reactions.

Research in that field began within DRECAM at the beginning of the 90's. They led to a revolution in physico-chemistry: the duration of the energy flow within organic or bio-organic molecules often scales within the sub-picosecond time range. This was at variance with the models usually used of redistribution of energy by coupling between electronic excitation and vibration.

The PLFA project is essential to offer a more complete approach: it allows at the same time energy studies, by adjusting the quantity of energy deposited in the system, selectivity by the accordability of the source and time studies at the femtosecond scale.

Detail of the PLFA Laser Platform

Detail of the PLFA Laser Platform

A recent work on the photo-dynamic of the radical t-butyl (C-(CH3)3) was undertaken on PLFA via a collaboration between the SPAM and the University of Würzburg (Germany) within the framework of European network LASERLAB. It produced a very first surprising result whose consequences remain to be evaluated. It is first observed that the characteristic time of energy redistribution depends on the quantity of energy deposited. This can be at first explained by considering that this energy makes the system more easily deformable authorizing faster energy redistribution. Contrary to all predictions, beyond deposition of some amount of energy, a qualitative change takes place and the redistribution becomes “very slow” (a few picoseconds compared with a hundred femtosecondes). This work has been recently published in J. Phys. Chem. A.

With this new laser platform, the laboratory gives at the disposal of the researchers the very essential tool to explore unknown facets of physico-chemistry.

Femtosecond Dynamics of the tert-Butyl Radical, t-C4H9
B. Noller, R. Maksimenka, I. Fischer, M. Armone, B. Engels, C. Alcaraz, L. Poisson, and J.-M. Mestdagh 
J. Phys. Chem. A, 111 (2007) 1771.

Effets coopératifs dans l'absorption du rayonnement UV par les bases de l'ADN
Last Update: 3 February 2014

Repliement de chaînes peptides en détente supersonique
Last Update: 3 February 2014

Formation of carbon nanotube multi-layers and identification of their growth mode
Last Update: 5 January 2010

Participation d'un état de Rydberg à la redistribution ultrarapide de l'énergie électronique du TDMAE [tetrakis(diméthylamino)éthylene]
Last Update: 3 February 2014