ɪn nˈɑːnɹˌɛləɾɪvˈɪstɪk kwˈɔntəm mᵻkˈænɪks, ðə tɹænsmˈɪʃən kˌoʊɪfˈɪʃənt ænd ɹᵻlˈeɪɾᵻd ɹᵻflˈɛkʃən kˌoʊɪfˈɪʃənt ɑːɹ jˈuːzd tə dᵻskɹˈaɪb ðə bᵻhˈeɪvjɚɹ ʌv wˈeɪvz ˈɪnsɪdənt ˌɔn ɐ bˈæɹiɚ.
In non-relativistic quantum mechanics, the transmission coefficient and related reflection coefficient are used to describe the behavior of waves incident on a barrier.