Direct Observation of transition states of the isomerization of HCP

为了从光谱上捕捉到HCP*CPH异构化的行为，我们观察到了HCP的高激发态振动能级，并分析了它们的振动结构。同时使用了分散荧光光谱和受激发射泵浦光谱。在这两种方法中，我们都用红外-紫外双共振技术成功地观测到了VCH激发态的振动能级。通常，在传统的光谱学研究中，振动本征能的再现是非常集中的。然而，我们对本征函数和本征能量都给予了关注。我们对一个有效的哈密顿矩阵进行了本征矢量分析，该矩阵考虑了弯曲模和CP伸缩模之间的费米型非谐共振。因此，本征矢分析很好地展示了高能区“异构化”态的产生，这是最近的理论研究预测的结果。在高能区，弯曲模式和CH伸缩模式之间的相互作用肯定是重要的：因此，预计将弯曲模式和CH伸展模式之间的相互作用纳入我们的方法将揭示关于HCP*CPH异构化反应动力学的更详细的信息。

In order to catch spectroscopically the act of HCP * CPH isomerization, we have observed highly excited vibrational levels of HCP and analyzed their vibrational structure. Both the dispersed fluorescence and stimulated emission pumping spectroscopies were utilized. We have succeeded to observe VCH excited vibrational levels by means of an application of the infrared-ultraviolet double resonance technique in both methods. In general, a reproduction of the vibrational eigenenergies is much concentrated in the traditional spectroscopic study. However, we paid an attention to eigenfuctions as well as eigenenergies. We have carried out the eigenvector analysis of an effective Hamiltonian matrix that takes into account of Fermi type anharmonic resonances between the bend and CP-stretch modes. As a result, the eigenvector analysis well exhibits a generation of the "isomerization" states in the high energy region, the generation of which has been predicted by recent theoretical studies. In much higher energy region, an interaction between the bend and CH stretch modes must be important : Thus, it is expected that the inclusion of the interaction between the bend and CH stretch modes into our approach will reveal much detailed information about dynamic in the HCP * CPH isomerization reaction.