THE H-2 EXCITATION BY FORMATION PUMPING IN THE MERGING GALAXY NGC-6240

The formation of H-2 molecules in high rotation-vibration levels leads to the excitation of H-2 emission in the infrared (formation pumping) . This process is important in dissociative molecular shocks, where H- 2 molecules are reformed behind the shock fronts. We calculate the H-2 spectra due to formation pumping, and compare them with the published data of NGC 6240, a galaxy-merger system. The comparison reveals the possible contribution from formation pumping to the H-2 excitation in NGC 6240. If this is the case, the molecule formation may be associate d with fast molecular shocks driven by the galaxy-galaxy collision.