Axially channeled electrons are captured into bound states of the "atomic-string" potential. When two rows lie in close proximity as in the $〈110〉$ direction of diamond, the potentials overlap, forming a saddle point between the rows. For 4-MeV electrons in the $〈110〉$ diamond potential, the $2p$ level lies above the saddle point, and molecular states are formed. The observation of radiation arising from transitions of these states is reported. Spectral information is used to deduce electron-density enhancement in the C-C bond.