Slowing Down Of Atoms In Metals Studied By The Doppler-Broadened Gamma-Ray Line Shapes Produced After Thermal-Neutron Capture In Fe And Cr Crystals

Molecular-dynamics simulations describing the slowing down of atoms in solids are used to study interatomic potentials in metals. This analysis is achieved by observing the fine structures of Doppler-broadened gamma rays emitted by the recoiling excited nuclei. The recoil of the atom, similar to 400 eV kinetic energy, is generated by the emission of a preceding gamma ray following thermal-neutron capture. The experiment was performed with oriented single crystals of Fe and Cr as target and high-resolution gamma-ray spectroscopy. Two different nuclear levels for each element were studied and the best interatomic potential among many available in the literature could be deduced from the data. The construction of a different potential was also investigated with this technique. Lifetime values with a much improved precision were obtained for four excited nuclear levels. [S0163-1829(99)01133-9].