NAMs中缺陷OH红外吸收的温度依赖行为的研究

IThe behavior of structural OH in clinopyroxene (Cpx), orthopyroxene (Opx) and plagioclase (Pl) during successive heating has been investigated by in-situ Micro-FTIR measurements under temperatures ranging from 25℃ to 500℃at 100℃ increment. The results suggest the IR spectra are reversible when the temperature reverses to 25℃. Both Cpx and Opx exhibit a decrease in the three groups of OH stretching vibration frequency with increasing temperature, and the three groups of OH band have different temperature shifts. However, Pl very broad band centered at about 3200cm-1 shifts to higher frequency with increasing temperature. The value and direction of the OH frequency shifts dν/dT are in associated with initial wavenumber. Whether pyroxene or plagioclase, increasing temperature leads to a general decrease in the peak height and peak area of OH fundamental stretching vibration. Different bands exhibit different temperature response in a mineral, while the total OH absorption area is decreasing with temperature increasing. But the varying area value with temperature dA/dT is associated with mineral types.