(300−400)cm−1 (300-400) \mathrm{cm}^{-1}(300−400)cm−1
<1000 cm−1<1000 \mathrm{~cm}^{-1}<1000 cm−1
(1000−4000)cm−1(1000-4000) \mathrm{cm}^{-1}(1000−4000)cm−1
<4000 cm−1<4000 \mathrm{~cm}^{-1}<4000 cm−1
