Université Paul Sabatier - Bat. 3R1b4 - 118 route de Narbonne 31062 Toulouse Cedex 09, France


février 2020 :

Rien pour ce mois

janvier 2020 | mars 2020

Rechercher





Accueil > Séminaires > 2014

Recent advances in quantum-chemical investigation of amorphous carbon structure and properties

Oleksiy Khavryuchenko, Kyiv National Taras Shevchenko University (Kiev, Ukraine)

Séminaire LCPQ/LCC

Salle de séminaire IRSAMC

Establishing a comprehensive model of amorphous carbons and computing their properties is an intense area of research due to the wide application of carbon materials and their practical importance. However, the majority of such models are still based solely on ordered graphite-like clusters or non-bonded curved carbon sheets.

In our investigation spatial structure of the amorphous domain cluster has been constructed from a series of different polymer-precursors models by simulation of carbonization through stepwise elimination of hydrogens and subsequent optimization of the geometry in different multiplicity states. The final geometry, being unique, is taken as an arbitrary model for a disordered amorphous domain as the one, representing typical statistic distribution of properties.

Conjugated carbon systems representative of both graphite-like and amorphous structures have recently been predicted to possess half-metallic properties. The pseudo-degeneracy of multiple spin states characteristic of half-multiplicity could lead to spin-induced structural transformations in these systems, and such systems could influence chemical reactions where spin is not necessarily conserved, i.e. serve as spin catalysts (or inhibitors). The latter proposal was investigated in two reactions : 1) C2H6 cracking into two CH3• radicals and 2) [2+2] cycloaddition of 2-butenes over both paramagnetic and diamagnetic partially oxidized graphite-like carbon clusters in various multiplicity states.

References :

Journal of Physical Chemistry C (2013), 117(12), 6225-6234.
Chemical Physics Letters (2011), 513(4-6), 261-266.