Fig. 3

Schematic of the DFT potential energy surfaces of \({{\rm C}}_{10}^ -\). The ground states of linear and monocyclic \({{\rm C}}_{10}^ -\) are shown by the solid lines. The energy shift due to rotational energy of the linear \({{\rm C}}_{10}^ -\) is set to 0 eV in the energy scale. The energy levels for monocyclic \({{\rm C}}_{10}^ -\) are shown relative to the linear \({{\rm C}}_{10}^ -\) energy scale. Due to conservation of rotational angular momentum during isomerization from linear to monocyclic \({{\rm C}}_{10}^ -\), the isomerization barrier as well as the energy levels of monocyclic \({{\rm C}}_{10}^ -\) will be shifted with respect to linear \({{\rm C}}_{10}^ -\) (shown by dashed lines). E_rot is the amount by which this shift occurs and is the difference of rotational energies between the linear and monocyclic \({{\rm C}}_{10}^ -\) with a particular rotational quantum number. The probability that the system is in a certain rotational state (with a particular quantum number) depends on the rotational temperature of the cluster at the time of laser interaction