Abstract
High-temperature equilibrium relative populations of two Ti2C2@C(82) isomers isolated recently are treated by quantum-chemical calculations, viz. endohedrals with the C (s)(c);6-C(82) and C (3v)(b);8-C(82) IPR (isolated-pentagon-rule) cages. The calculations are carried out using the Gibbs energy based on the MP2=FU/6-31+G*&-SDD energetics and B3LYP/6-31G*&-SDD entropy.
The observed ratio Ti2C2@C(s)(c);6-C(82) : Ti2C2@C(3v)(b);8-C(82)=1.6:1 is in the computations obtained at a temperature of 1543 K, i.e., in the supposed synthetic temperature region. Before that point, the two isomers reach their equimolarity at a temperature of 983 K.
This fine theory-experiment agreement represents another example of a good performance of the Gibbs-energy based quantum-chemical evaluations of the fullerenic equilibrium compositions under the high-temperature synthetic conditions.