Mapping intermolecular bonding in C??.

ABSTRACT: The formation of intermolecular bonds in C?? has been investigated in detail at pressures below 2.2?GPa and up to 750?K. Fullerene samples were heated in a temperature gradient to obtain data on the formation of dimers and low-dimensional polymers along isobars. Intermolecular bonding was analyzed ex situ by Raman scattering, using both intramolecular modes and intermolecular stretching modes. Semi-quantitative reaction maps are given for the formation of dimers and chains. The activation energy for dimer formation decreases by 0.2?meV pm(-1) when intermolecular distances decrease and dimer formation is noticeably affected by the rotational state of molecules. Above 400-450?K larger oligomers are formed; below 1.4?GPa most of these are disordered, with small domains of linear chains, but above this the appearance of stretching modes indicates the existence of ordered one-dimensional polymers. At the highest pressures and temperatures two-dimensional polymers are also observed.

SUBMITTER: Sundqvist B 

PROVIDER: S-EPMC4141248 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature