Title :

Dynamics in the BMIM PF6/acetonitrile mixtures observed by femtosecond optical Kerr effect and molecular dynamics simulations.

Author(s) :

Polok, K. [Auteur]
Beisert, Matthieu [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 [LASIRE]
Swiątek, A. [Auteur]
Maity, Nishith [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 [LASIRE]
Piatkowski, P. [Auteur]
Gadomski, W. [Auteur]
Miannay, Francois-Alexandre [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516
Idrissi, Nacer [Auteur]
Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516

Journal title :

Physical Chemistry Chemical Physics

Abbreviated title :

Phys Chem Chem Phys

Publication date :

2020-10-24

ISSN :

1463-9084

HAL domain(s) :

Chimie/Chimie théorique et/ou physique

English abstract : [en]

We have performed the measurements of the optical Kerr effect signal time evolution up to 4 ns for a mixture of 1-alkyl-3-methyl-imidazolium hexafluorophosphate (BMIM PF6) ionic liquid and acetonitrile in the whole mole ...
Show more >We have performed the measurements of the optical Kerr effect signal time evolution up to 4 ns for a mixture of 1-alkyl-3-methyl-imidazolium hexafluorophosphate (BMIM PF6) ionic liquid and acetonitrile in the whole mole fractions range. The long delay line in our experimental setup allowed us to capture the complete reorientational dynamics of the ionic liquid. We have analysed the optical Kerr effect signal in the time and frequency domains with help of molecular dynamics simulations. In our approximation of the slow picosecond dynamics with a multi-exponential decay, we distinguish three relaxation times. The highest two are assigned to the reorientation of the cation and acetonitrile molecules that are in the vicinity of the imidazolium ring. The third one is recognized as originating from cation rotations and reorientation of acetonitrile molecules in the bulk or in the vicinity of the aliphatic chains of the cation. With help of the simulation we interpret the intermolecular band in the reduced spectral density, obtained from Kerr signal, as follows: its low-frequency side results from oscillations of one of the components in the cage formed by its neighbors, while the high-frequency side is attributed to the librations of the cation and acetonitrile molecule as well as the intermolecular oscillations of system components involved in specific interactions. We use this assignment and concentration dependence of the spectra obtained from velocity and angular velocity correlations to explain the mole fraction dependence of Kerr reduced spectral density.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS

Collections :

• Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement (LASIRE) - UMR 8516

Submission date :

2024-02-28T22:51:51Z
2024-03-12T15:19:23Z