Energy required to dissociate a molecule into two parts. Subscripts 0 and e, i.e. D0 and De, are used to denote the dissociation from the ground state and potential energy minimum, respectively.
See also: bond-dissociation energy
Source:
Green Book, 2nd ed., p. 20 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)