Coherent Raman spectroscopy of nuclear quadrupole resonance of La around Pr3+ in LaF3

Coherent Raman spectroscopy was applied for an optical-rf double-resonance study of a LaF3 crystal doped with Pr3+. The coherent nuclear spin Raman sc attering was detected as a function of the applied rf frequency. Exciting t he resonance condition of the H-3(4)-->P-3(0) transition of Pr3+ (20925 cm( -1)), only the La nuclei surrounding the Pr3+ ion were observed through the ir nuclear quadrupole resonance (NQR). The double resonance between the opt ical transition of the ion and the NQR transition of its neighboring nucleu s is theoretically described by analyzing the magnetic dipolar interaction that is affected by the optical excitation. Under a certain restriction, wh ich the present system fulfills, the intensity of the Raman heterodyne sign al can be described by an analytical function of the internuclear vector an d the orientation of the electric-held gradient (EFG) at the Pr and La nucl ei. Five different neighboring La nuclei were observed. They are different from the bulk La in both magnitude and orientation of the EFG. In addition, it was found that the laser frequency jitter affects the relative signal i ntensity of the different La NQR transitions through the optical pumping of the La spin levels, [S0163-1829(98)03145-2].