ˈɛf zˈiəɹoʊ ɪz ðə lˈoʊ flʊɹɹˈɛsəns ɪntˈɛnsᵻɾi, wˌɪtʃ ɪz mˈɛʒɚd baɪ ɐ ʃˈɔːɹt lˈaɪt flˈæʃ ðæt ɪz nˌɑːt stɹˈɔŋ ɪnˈʌf tə kˈɔːz fˌoʊɾoʊkˈɛmɪstɹi, ænd ðˈʌs ɪndˈuːsᵻz flʊɹɹˈɛsəns.
F0 is the low fluorescence intensity, which is measured by a short light flash that is not strong enough to cause photochemistry, and thus induces fluorescence.