Liquid argon and liquid xenon are interesting media for Liquid Ionization Detectors (LID). The high atomic number and the high density of liquid xenon results in a gamma-ray efficiency similar to that of Nal(Tl) crystals. At the same time, the W-value and the low Fano factor point at energy resolutions close to that of Ge(Li) spectrometers. However, no one has come close to achieving this predicted energy resolution. In order to try understand the reason(s) for this discrepancy, several experiments have been carried out using both liquid argon and liquid xenon. For LAr a total energy resolution of 30.5 keV (41.7 keV) is obtained for the 481 keV (975 keV) K-conversion electrons. The energy resolution for LXe is 49 keV (65 keV) for the 570 keV (1064 keV) photopeak. The energy resolutions obtained are discussed with respect to their energy dependence. The influence of electro-negative impurities and recombination effects are discussed. The free carrier yield for 5.4 MeV alpha-particles and its dependence on the electrical field are reported for LXe.