In this paper, the structure of CO2 clusters made of less than a hundred of molecules is studied by means of electron diffraction experiments and molecular dynamics simulations. According to previous works, CO2 clusters are expected to undergo a transition in this size range, from an icosahedral structure to the bulk cubic structure. Electron diffraction patterns have been recorded from clusters produced in a free jet expansion of gaseous CO2. These patterns provide evidence of a structural change occurring in clusters made of a few tens of molecules. (CO2)(N) models, with 13

Keywords:CARBON-DIOXIDE CLUSTERS;INFRARED-SPECTROSCOPY;MOLECULAR CLUSTERS;NONCRYSTALLINE STRUCTURE;PHASE-TRANSITIONS;ARGON CLUSTERS;CO2 CLUSTERS;DYNAMICS;SIZE;CH4