Quantum Theoretical Study on Single, Double and Triple Bonds between Carbon Atoms

Abstract

We study the characteristic features of single, double and triple bonds between carbon atoms by idealizing the problem to the electronic structure of fictitious diatomic molecules ≡C–C≡, =C=C= and –C≡C–, where the “open” bonds of carbon atoms are represented by a suitably hybridized orbitals, associated with free spins. Thus, adiabatic potentials are non-empirically and numerically computed and bond energies and equilibrium internuclear distances are evaluated. We obtain 3.1 e.v., 1.25 e.v. and 0.20 Å, 0.10 Å for the values of relative bond energy differences and bond distance differences of single and triple, double and triple bonding. The corresponding experimental values are 2.9 e.v., 1.0 e.v., and 0.34 Å, 0.12 Å respectively.