Mössbauer Experiments with Coulomb‐Excited 73 Ge after Coulomb Recoil Implantation

The nuclear resonance absorption of the 67.03 keV de‐excitation radiation of 73 Ge * , Coulomb‐excited by 20 to 30 MeV 16 O ions, is studied. The recoiling 73 Ge ° nuclei are implanted into a chromium substrate. The electronic configurations Ge (4s 1 p 3 ) in Ge (cryst.), Ge (15% (4s 2 p 0 ), 85% (4s 2 p 2 )) in Ge (II)Se, Ge (62% (4s 0 p 0 ), 38% (4s 1 p 3 )) in GeO 2 (hex.) and GeO 2 (tetr.), and the ratio δ R/R =1.12 × 10 −3 of the nuclear charge radius are compatible with the measured isomeric shifts. Line broadenings and recoil‐free fractions f of the implantation target and the absorbers are determined. At 78 °K f   GeO   2 (tetr.)is greater than f   GeO   2 (hex.)by a factor of six.