By means of Zeeman anisotropy fluorescence (ZAF) and its field dependence (up to 55.8 kG), the authors have investigated the 4.2 K narrow-line fluorescence of KCl:Sm2+ and identified some hitherto unreported Sm2+ sites. The strong no-field line at 7693.5 Å (5D0→7F3) and a very weak no-field line at 8742.8 Å (5D0→7F5) are shown to be of C3v symmetry origin. The 24.5-kG ZAF pattern observed in the 7696-7700-Å (5D0→7F3) region has been identified to originate from a type-II Cs site. The 26.5-kG ZAF patterns of the C3v no-field line at 7693.5 Å and the type-I Cs no-field line at 7694.5 Å overlap in the 7693-7695.3-Å region, and are elucidated through the field dependence of their Zeeman components. Characteristic radiative lifetimes of the 5D0 level in several Sm2+ symmetry types have been determined from dominant transitions to the 7FJ (J\u3c~4) levels. There are two distinct C4v sites: one with a lifetime of 9.5 msec, and the other 11.2 msec. C2v and type-I Cs sites have lifetimes of 10.5 and 10.8 msec, respectively, which are indistinguishable within the experimental error. The role of O2− compensation of Sm2+ in addition to K+ vacancy compensation in KCl is discussed in terms of these findings
