 |
||
   |
||
| Atomic Physics » Research » Gas phase fullerenes and clusters | ||
| Some of our current interests We are investigating the dynamics of (C60)N clusters after exciation by femto second laser pulses. The clusters are created in a gas aggregation source and after interaction with the laser they are investigated the reflectron time of flight mass spectrometer. The clusters seem to fuse which is different from what is observed after exciation by ns-pulses or high energetic ion collisions. The dynamics of the processes are examined by using both C60 and C70, different settings of the aggregation source and pump-probe measurements. Radiative cooling from C70 and other fullerenes Highly excited fullerenes will lose energy due to ionisation, fragmentation and photon emission. When excited by a laser pulse in our reflectron time-of-flight mass spectrometer the fullerenes will decay by all these mechanisms, we can only detect those that have ionised. We can further on distinguise between the species that have ionised and fragmented a number of times. If the reflectron is tuned correctly it is possible to get the fullerenes that fragment promptly and the ones that fragment during their flight (metastable) to appear as two different peaks in the mass spectrum. By studying the amount of metastable fragmentation as compared to prompt fragmentation as a function of flight times in our mass spectrometer we can learn more about the radiative cooling of the fullerenes. If the excited fullerenes are extracted from the ionisation region delayed (they are accelerated with some delay with respect to the exciting laser pulse) they will have more time to lose energy due to photon emission and the energy available for metastable fragmentation is lower and thus the ratio between the prompt fragmentation peak and the metastable peak will be changed. By studying this change and doing some statistical modeling we can find information on the radiative cooling rate and we can compare cooling from fullerenes with enohedral fullerenes like La@C84. 
C2 and C4 emission from C60
We study the competition and branching ratios between C2 and C4 emission from highly excited C60 theoretically. |
