New experimental and theoretical assessment of the dissociation energy of C2

The dissociation energy in the X1Σg+ electronic ground state of the carbon dimer C2 is determined spectroscopically from a combined treatment involving resonant four-wave mixing experiments and highly accurate multi-reference configuration interaction calculations to be (50370±150)hccm−1  ((6.24±0.02) eV, (602±2) kJ mol−1). This new value allows us to clarify current discrepancies among other experimental and theoretical results, which will be discussed.