The theory of concerted electronic and nuclear flux densities associated with the vibration and dissociation of a multielectron nonrotating homonuclear diatomic molecule (or ion) in an electronic state (2S+1)Sigma(+)(g,u) (JM = 00) is presented. The electronic population density, nuclear probability density, and nuclear flux density are isotropic. A theorem of Barth , presented in this issue, shows that the electronic flux density (EFD) is also isotropic. Hence, the evolving system appears as a pulsating, or exploding, "quantum bubble". Application of the theory to Na-2 vibrating in the double-minimum potential of the 2 (1)Sigma(+)(u) (JM = 00) excited state reveals that the EFD consists of two antagonistic components. One arises from electrons that flow essentially coherently with the nuclei. The other, which is oppositely directed (i.e., antagonistic) and more intense, is due to the transition in electronic structure from "Rydberg" to "ionic" type as the nuclei traverse the potential barrier between inner and outer potential wells. This "transition" component of the EFD rises and falls sharply as the nuclei cross the barrier.