The temperature effect of nuclear resonance scattering from the 6.324 MeV level in 15N was studied as a function of temperature using a gaseous 15N2 target and a solid Li15NO3 target. The γ-source was produced by the Cr(n, γ) reaction using thermal neutrons. In order to reproduce the experimental variation of the scattering cross section versus temperature, the Lamb treatment for metallic elements was generalised to the case of diatomic and more complicated molecules. In 15N2 an effective temperature was defined in which the zero-point energy of vibration of the diatomic molecule was included. In LiNO3, an effective temperature was also defined by introducing a modified Debye temperature and accounting for the normal modes of vibration of 15N in the 15NO3- molecule. An excellent agreement between measured and calculated values was obtained. In a way, the present measurement may be viewed as detecting the zero-point vibrations in molecules.
- Nuclear Reaction
ASJC Scopus subject areas
- Nuclear and High Energy Physics