In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: phenomenon can be modified by the Goldanskii-Karyagin effect, allowing detection of anisotropies in the mean-square displacements of randomly-oriented systems when there is quadrupole and/or magnetic splitting in resolved hyperfine structure in its spectrum. As with X-ray and neutron scattering, the Debye-Waller factor can be used to calculate the fraction of emission or absorption events displaying this phenomenon. It was first seen in iridium-191, but this phenomenon of nuclear resonance fluoresence is more often observed using samples of iron-57. FTP, name this phenomenon in which a crystal lattice absorbs or emits a gamma ray with zero recoil.
A:
Science