固体样品的光声位相理论及应用研究

Studies on the Theory and Applications of the Photoacoustic Phase of Solid Sample

在Ｒ－Ｇ理论的基础上，考虑了无辐射弛豫过程对位相信号的影响，推导出新的位相公式．研究结果表明，位相（ψ）与吸收系数（β）、热扩散长（μ）、弛豫时的延迟时间（τ）和快弛豫与慢弛豫时的热量比（Ｒ）有关．并用此公式解释了稀土化合物ＰｒＦ３和叶绿素ｂ的位相谱．ＰｒＦ３的位相由ｆ－ｆ跃迁的吸收系数决定，而叶绿素ｂ两个吸收带之间的位相差是由快弛豫与慢弛豫时放出的热量比不同产生的．

Based on the R-G theory of the photoacoustic effect, a new formula on the PA phase was presented while the phase caused by non-radiative relaxation processes was considered. The phase is associated with the absorption coefficient(β), thermal diffusion length of sample(μs), the delay time of relaxation(τ) and the ratio of the heat component(R) of rapid relaxation to that of slow one. The phase spectra of PrF3 and chlorophyll b were explained well by using of this formula. The phase of PrF3 is determined by the absorption coefficient for the f-f transition. The phase difference between the two bands of chlorophyll b is caused by the different heat component ratios of rapid relaxation to slow one.