Plasmas can emit radiation based on the acceleration of charged particles (which we generally consider as continuous), but for un-ionized matter compounds, transitions are quantized and photons have particular energies. At room temperature, collisional excitations are typically dominant. But if that is the case, what about blackbodies permits continuous spectra at all wavelengths? Why do certain materials (e.g. carbon nanotube structures) approximate well this behaviour despite being finite in size and available energy levels? Why do we not discuss/observe blackbody emissions as having discrete energies?