New electronic transitions of the C2 molecule in absorption in the vacuum ultraviolet region

Three new electronic transitions of the C 2 molecule have been observed in absorption in the region 1300–1450 Å. The system of shortest wavelength is readily identified as a 1 Π u – 1 Σ g + transition; the lower state is the ground state X 1 Σ g + of the molecule. The other two systems arise by absorption from the low-lying a 3 Π u state; the upper states are new 3 Σg − and 3 Δ g states. Rotational and vibrational constants of the three new states have been determined. The new states are Rydberg states. Their correlation to the separated atoms is briefly discussed.