Tomographic imaging of molecular orbitals

确定分子结构的方法有很多种。电子和x射线散射测量平均电子密度，而光谱学可以确定电子结构的对称性。我们最近表明，使用强飞秒激光从气相分子产生的高谐波可以揭示分子电子结构的细节。我们称这项技术为分子轨道断层扫描。我们证明了我们可以形成二氮的单电子分子轨道波函数的图像[Itatani et al., Nature 432, 867(2004)]。这种方法可以特定于单个轨道波函数，这在化学物理学界引起了极大的兴趣。该技术提供了优于埃的空间分辨率和小于30飞秒的时间分辨率。我们相信100阿秒的分辨率也是可能的，从而可以观察到原子中的电子波包运动。我们建议将测量扩展到其他分子。我们还计划用这种技术来观察分子内部的动力学过程。在解离过程中，由于曲线的交叉，也可能观察到电子对称性的变化。

There are numerous methods by which molecular structure may be determined.  Electron and x-ray scattering measure the average electron density, whereas spectroscopy can determine symmetry properties of the electronic structure. We recently showed that high harmonic generation from gas phase molecules using intense femtosecond laser light can reveal details of the electronic structure of molecules.  We called the technique molecular orbital tomography.  We showed that we could form an image of a single electron molecular orbital wave function of dinitrogen [Itatani et al., Nature 432, 867 (2004)].  That this method could be specific to a single orbital wave function has created a great deal of interest in the chemical physics community. This technique provides spatial resolution of better than an Angstrom and temporal resolution of less than 30 femtoseconds.  We believe that 100 attosecond resolution may also be possible, leading to observation of electron wavepacket motion in atoms. We propose to extend measurements to other molecules.  We also plan to use this technique to observe a dynamical process within a molecule.  It may also be possible to observe a change in electronic symmetry due to curve crossing during dissociation.