Goldanskii-karyagin effect at mössbauerE2-transitions

Investigations of anisotropic Debye-Waller factors have been carried out mainly using the M1-transitions of⁵⁷Fe and¹¹⁹Sn. For this case the theory of the Goldanskii Karyagin effect is well established. Mössbauer studies of electric quadrupole interactions in hafnium and tungsten compounds made it necessary to extend the theory to the more complex case of E2-transitions. As the investigated compounds show a strong axial anisotropy of the electric field gradient, a similar behaviour has to be expected in principle for the tensor of the mean-square displacements, which determines the Debye-Waller factor immediately. A fitting procedure taking into account an axial asymmetric Debye Waller factor is worked out and applied to measurements performed with several complex hafnium and tungsten fluorine compounds. With NaWO₂F₃ the quadrupole interactions of¹⁸²W,¹⁸³W, and¹⁸⁴W have been measured yieldingQ ^5/2+(¹⁸³W)/Q ²+(¹⁸²W)=0-86(6) andQ ²+(¹⁸⁴W)/Q ²+(¹⁸²W)=0.955 (3).