  We present a systematic study of the time and band-resolved scintillation in
xenon-based time projection chambers (TPCs), performed simultaneously for the
primary (S1) and secondary (S2) components in a small, purity-controlled,
setup. We explore a range of conditions of general academic interest, focusing
on those of relevance to contemporary TPCs: pressure range ([1- 10] bar),
pressure-reduced electric fields ([0-100] V/cm/bar in the drift region (S1) and
up to the proportional scintillation regime in the multiplication region (S2)),
wavelength-band ([145-250], [250-400], [400-600] nm), and primary excitation
($\alpha$, $\beta$-particles). Attention is paid to the possibility of
non-conventional scintillation mechanisms such as the 3rd continuum emission,
recombination light from $\beta$-electrons at high pressure (for S1), emission
from high-lying excited states and neutral bremsstrahlung (for S2). Time
constants and, specially, scintillation yields have been obtained as a function
of electric field and pressure, the latter aided by Geant4 simulations.
