光腔衰荡光谱方法研究正丙醇羟基泛频光谱和分子构象

用高灵敏的光腔衰荡光谱(Cavity Ring－Down Spectroscopy)方法探测到了正丙醇波长在620和700 nm附近的高激发泛频振动光谱，将其归属于分子不同稳定构象的O－H伸缩振动（υ＝4、5）泛频吸收，谱带用高斯函数模拟后得到的每一个峰都对应于分子的一个或几个稳定构象。用局域模理论（Local Mode Theory)对同一分子的不同泛频振动(υ值不同）进行了分析指认，求出了分子羟基振动的机械振动频率常数ωe，非谐性振动常数ωeχe。与已知甲醇的常数进行了比较，得到了令人满意的结果。用密度泛函理论（DFT）、B3LYP/6－311+G**方法优化了正丙醇各种可能的稳定构象，计算所得结果与试验值吻合。

The O-H Stretching Vibrational Overtones and Molecular Conformations of n-Propanol by CRD Spectroscopy

The O-Hstretching vibrational overtone spectroscopy(υ= 4,5 ) ofn-propanol are mea-sured by Cavity Ring Down Spectroscopy (CRDS), where two peaks are observed for each level.These bands are simulated by several Gauss functions.They are assigned to the absorption of the O-Hstretch-ing vibrations of molecular conformations. The mechanical frequenciesωe, anharmonicitiesωeχeand dis-sociation energiesDare evaluated by Local Mode Theory(LM). The possible conformations of molecular are alsooptimized by Density Function Theory(DFT), B3LYP/6-311+G ** methodsand the cacu-lated O-Hstretching frequencies and stability are in good agreement with the experimental results.