Cotton effect

…However, the measured optical rotatory dispersion curve changes sign around λ ₀ , taking finite values, as shown by the solid line [2]. This phenomenon of anomalous dispersion, in which the value of specific rotation changes suddenly, is called the Cotton effect. When the value of [α] or [ M ] is negative on the long-wavelength side of λ ₀ and positive on the short-wavelength side, as shown by the curve [2], it is called the negative Cotton effect, and when it changes from positive to negative, it is called the positive Cotton effect. …

*Some terminology explanations that mention the "Cotton effect" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…ところが実測の旋光分散曲線は，実線[2]のようにλ₀のまわりで有限な値をとりながら符号を変化する。このように，比旋光度の値が急激に変化する異常分散の現象をとくにコットン効果Cotton effectと呼ぶ。曲線[2]のようにλ₀の長波長側で[α]または[M]の値が負で，短波長側で正となる場合を負のコットン効果と呼び，逆に正から負に変わる場合を正のコットン効果という。…

※「Cotton effect」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報