Site-selective fluorescence excitation spectroscopy of a KMgF 3:Sm 2+ crystal

Abstract

We investigate the defect structure of KMgF 3:Sm 2+ by site-selective laser spectroscopy. The transitions between 5 D 0 and 7 F J ( J=0, 1 and 2) states of Sm 2+ in KMgF 3 strictly obey induced electric dipole (ED) and magnetic dipole (MD) selection rules and symmetry selection rules from which three dominant sites with O h, C 4v and C 2v symmetries and two minor C 3v sites are identified at 11 K. The sites with C 4v and C 2v symmetries are assigned to Sm 2+ with the vacancies at the nearest-neighbor K + site along the [1 0 0] direction and at the second-nearest-neighbor K + site along the [1 1 0] direction, respectively. It is assumed that the two C 3v sites do not come from Sm 2+ with the third-nearest-neighbor K + vacancy along the [1 1 1] direction but from Sm 2+ associated with other defects.