Study of possible photodissociation channels in linear carbon clusters Cn (n=4–6)

Ab initio calculations are used to determine molecular properties of linear carbon clusters Cn (n=3–6) in ground and electronically excited states relative to photodissociation processes. MRD-CI calculations predict that in C3 and C5 the singlet–triplet splitting between the 1Πu and 3Πu arising from the same configuration is about 1 eV similar as in C2. The energy differences between 1Δg and 1Σg+ corresponding to the same πg2 or πu2 configuration in C4 and C6 are less than 0.2 eV. Calculations support experimental finding that the energetically most favorable fragmentation channel for linear carbon clusters Cn (n=4–6) corresponds to the loss of C3 to give its partner fragment Cn−3. Further fragmentation channels are discussed.