Theoretical study of C2 and C2−

Abstract
Potential energy curves of the ground states of C2(X 1Σg+) and C2(X 2Σg+) have been calculated using SCF, MCSCF, and CI methods. Close agreement with experimental dissociation energies, bond lengths, and spectroscopic constants is obtained by a CI calculation including all single and double excitations from the restricted Hartree–Fock configuration, with corrections for the quadrupole excitations estimated by a formula due to Davidson. The restricted Hartree–Fock method overestimates the electron affinity of C2, giving a value 4.33±0.02 eV to be compared with the experimental value of 3.54±0.05 eV. The effect of higher excitations on calculated electron affinity has been investigated, and some general conclusions regarding the computation of molecular electron affinity have been drawn.

This publication has 16 references indexed in Scilit: